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Espaço de Hilbert – Wikipédia, a enciclopédia livre
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vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Lei_do_Paralelogramo"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Lei do Paralelogramo</span> </div> </a> <button aria-controls="toc-Lei_do_Paralelogramo-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Alternar a subsecção Lei do Paralelogramo</span> </button> <ul id="toc-Lei_do_Paralelogramo-sublist" class="vector-toc-list"> <li id="toc-Proposição_[2]" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Proposição_[2]"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Proposição <sup><span>[</span>2<span>]</span></sup></span> </div> </a> <ul id="toc-Proposição_[2]-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Ver_também" class="vector-toc-list-item vector-toc-level-1 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id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Conteúdo" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" title="Índice" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Alternar o índice" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Alternar o índice</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Espaço de Hilbert</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Ir para um artigo noutra língua. Disponível em 59 línguas" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-59" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">59 línguas</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-af mw-list-item"><a href="https://af.wikipedia.org/wiki/Hilbert-ruimte" title="Hilbert-ruimte — africanês" lang="af" hreflang="af" data-title="Hilbert-ruimte" data-language-autonym="Afrikaans" data-language-local-name="africanês" class="interlanguage-link-target"><span>Afrikaans</span></a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%81%D8%B6%D8%A7%D8%A1_%D9%87%D9%8A%D9%84%D8%A8%D8%B1%D8%AA" title="فضاء هيلبرت — árabe" lang="ar" hreflang="ar" data-title="فضاء هيلبرت" data-language-autonym="العربية" data-language-local-name="árabe" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Espaciu_de_Hilbert" title="Espaciu de Hilbert — asturiano" lang="ast" hreflang="ast" data-title="Espaciu de Hilbert" data-language-autonym="Asturianu" data-language-local-name="asturiano" class="interlanguage-link-target"><span>Asturianu</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/Hilbert_f%C9%99zas%C4%B1" title="Hilbert fəzası — azerbaijano" lang="az" hreflang="az" data-title="Hilbert fəzası" data-language-autonym="Azərbaycanca" data-language-local-name="azerbaijano" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-ba mw-list-item"><a href="https://ba.wikipedia.org/wiki/%D0%93%D0%B8%D0%BB%D1%8C%D0%B1%D0%B5%D1%80%D1%82_%D0%B0%D1%80%D0%B0%D1%83%D1%8B%D2%93%D1%8B" title="Гильберт арауығы — bashkir" lang="ba" hreflang="ba" data-title="Гильберт арауығы" data-language-autonym="Башҡортса" data-language-local-name="bashkir" class="interlanguage-link-target"><span>Башҡортса</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%A5%D0%B8%D0%BB%D0%B1%D0%B5%D1%80%D1%82%D0%BE%D0%B2%D0%BE_%D0%BF%D1%80%D0%BE%D1%81%D1%82%D1%80%D0%B0%D0%BD%D1%81%D1%82%D0%B2%D0%BE" title="Хилбертово пространство — búlgaro" lang="bg" hreflang="bg" data-title="Хилбертово пространство" data-language-autonym="Български" data-language-local-name="búlgaro" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%B9%E0%A6%BF%E0%A6%B2%E0%A6%AC%E0%A6%BE%E0%A6%B0%E0%A7%8D%E0%A6%9F_%E0%A6%9C%E0%A6%97%E0%A7%8E" title="হিলবার্ট জগৎ — bengalês" lang="bn" hreflang="bn" data-title="হিলবার্ট জগৎ" data-language-autonym="বাংলা" data-language-local-name="bengalês" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Espai_de_Hilbert" title="Espai de Hilbert — catalão" lang="ca" hreflang="ca" data-title="Espai de Hilbert" data-language-autonym="Català" data-language-local-name="catalão" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%D8%A8%DB%86%D8%B4%D8%A7%DB%8C%DB%8C%DB%8C_%DA%BE%DB%8C%D9%84%D8%A8%DB%8E%D8%B1%D8%AA" title="بۆشاییی ھیلبێرت — curdo central" lang="ckb" hreflang="ckb" data-title="بۆشاییی ھیلبێرت" data-language-autonym="کوردی" data-language-local-name="curdo central" class="interlanguage-link-target"><span>کوردی</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Hilbert%C5%AFv_prostor" title="Hilbertův prostor — checo" lang="cs" hreflang="cs" data-title="Hilbertův prostor" data-language-autonym="Čeština" data-language-local-name="checo" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Hilbertrum" title="Hilbertrum — dinamarquês" lang="da" hreflang="da" data-title="Hilbertrum" data-language-autonym="Dansk" data-language-local-name="dinamarquês" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Hilbertraum" title="Hilbertraum — alemão" lang="de" hreflang="de" data-title="Hilbertraum" data-language-autonym="Deutsch" data-language-local-name="alemão" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%A7%CF%8E%CF%81%CE%BF%CF%82_%CE%A7%CE%AF%CE%BB%CE%BC%CF%80%CE%B5%CF%81%CF%84" title="Χώρος Χίλμπερτ — grego" lang="el" hreflang="el" data-title="Χώρος Χίλμπερτ" data-language-autonym="Ελληνικά" data-language-local-name="grego" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-en badge-Q17437798 badge-goodarticle mw-list-item" title="artigo bom"><a href="https://en.wikipedia.org/wiki/Hilbert_space" title="Hilbert space — inglês" lang="en" hreflang="en" data-title="Hilbert space" data-language-autonym="English" data-language-local-name="inglês" class="interlanguage-link-target"><span>English</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Hilberta_spaco" title="Hilberta spaco — esperanto" lang="eo" hreflang="eo" data-title="Hilberta spaco" data-language-autonym="Esperanto" data-language-local-name="esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Espacio_de_Hilbert" title="Espacio de Hilbert — espanhol" lang="es" hreflang="es" data-title="Espacio de Hilbert" data-language-autonym="Español" data-language-local-name="espanhol" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Hilberti_ruum" title="Hilberti ruum — estónio" lang="et" hreflang="et" data-title="Hilberti ruum" data-language-autonym="Eesti" data-language-local-name="estónio" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Hilberten_espazio" title="Hilberten espazio — basco" lang="eu" hreflang="eu" data-title="Hilberten espazio" data-language-autonym="Euskara" data-language-local-name="basco" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%81%D8%B6%D8%A7%DB%8C_%D9%87%DB%8C%D9%84%D8%A8%D8%B1%D8%AA" title="فضای هیلبرت — persa" lang="fa" hreflang="fa" data-title="فضای هیلبرت" data-language-autonym="فارسی" data-language-local-name="persa" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Hilbertin_avaruus" title="Hilbertin avaruus — finlandês" lang="fi" hreflang="fi" data-title="Hilbertin avaruus" data-language-autonym="Suomi" data-language-local-name="finlandês" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Espace_de_Hilbert" title="Espace de Hilbert — francês" lang="fr" hreflang="fr" data-title="Espace de Hilbert" data-language-autonym="Français" data-language-local-name="francês" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Espazo_de_Hilbert" title="Espazo de Hilbert — galego" lang="gl" hreflang="gl" data-title="Espazo de Hilbert" data-language-autonym="Galego" data-language-local-name="galego" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%9E%D7%A8%D7%97%D7%91_%D7%94%D7%99%D7%9C%D7%91%D7%A8%D7%98" title="מרחב הילברט — hebraico" lang="he" hreflang="he" data-title="מרחב הילברט" data-language-autonym="עברית" data-language-local-name="hebraico" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Hilbert-t%C3%A9r" title="Hilbert-tér — húngaro" lang="hu" hreflang="hu" data-title="Hilbert-tér" data-language-autonym="Magyar" data-language-local-name="húngaro" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D5%80%D5%AB%D5%AC%D5%A2%D5%A5%D6%80%D5%BF%D5%B5%D5%A1%D5%B6_%D5%BF%D5%A1%D6%80%D5%A1%D5%AE%D5%B8%D6%82%D5%A9%D5%B5%D5%B8%D6%82%D5%B6" title="Հիլբերտյան տարածություն — arménio" lang="hy" hreflang="hy" data-title="Հիլբերտյան տարածություն" data-language-autonym="Հայերեն" data-language-local-name="arménio" class="interlanguage-link-target"><span>Հայերեն</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Ruang_Hilbert" title="Ruang Hilbert — indonésio" lang="id" hreflang="id" data-title="Ruang Hilbert" data-language-autonym="Bahasa Indonesia" data-language-local-name="indonésio" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-is mw-list-item"><a href="https://is.wikipedia.org/wiki/Hilbert-r%C3%BAm" title="Hilbert-rúm — islandês" lang="is" hreflang="is" data-title="Hilbert-rúm" data-language-autonym="Íslenska" data-language-local-name="islandês" class="interlanguage-link-target"><span>Íslenska</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Spazio_di_Hilbert" title="Spazio di Hilbert — italiano" lang="it" hreflang="it" data-title="Spazio di Hilbert" data-language-autonym="Italiano" data-language-local-name="italiano" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E3%83%92%E3%83%AB%E3%83%99%E3%83%AB%E3%83%88%E7%A9%BA%E9%96%93" title="ヒルベルト空間 — japonês" lang="ja" hreflang="ja" data-title="ヒルベルト空間" data-language-autonym="日本語" data-language-local-name="japonês" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%ED%9E%90%EB%B2%A0%EB%A5%B4%ED%8A%B8_%EA%B3%B5%EA%B0%84" title="힐베르트 공간 — coreano" lang="ko" hreflang="ko" data-title="힐베르트 공간" data-language-autonym="한국어" data-language-local-name="coreano" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-ky mw-list-item"><a href="https://ky.wikipedia.org/wiki/%D0%93%D0%B8%D0%BB%D1%8C%D0%B1%D0%B5%D1%80%D1%82_%D0%BC%D0%B5%D0%B9%D0%BA%D0%B8%D0%BD%D0%B4%D0%B8%D0%B3%D0%B8" title="Гильберт мейкиндиги — quirguiz" lang="ky" hreflang="ky" data-title="Гильберт мейкиндиги" data-language-autonym="Кыргызча" data-language-local-name="quirguiz" class="interlanguage-link-target"><span>Кыргызча</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Hilberto_erdv%C4%97" title="Hilberto erdvė — lituano" lang="lt" hreflang="lt" data-title="Hilberto erdvė" data-language-autonym="Lietuvių" data-language-local-name="lituano" class="interlanguage-link-target"><span>Lietuvių</span></a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/%D0%A5%D0%B8%D0%BB%D0%B1%D0%B5%D1%80%D1%82%D0%B8%D0%B9%D0%BD_%D0%BE%D1%80%D0%BE%D0%BD_%D0%B7%D0%B0%D0%B9" title="Хилбертийн орон зай — mongol" lang="mn" hreflang="mn" data-title="Хилбертийн орон зай" data-language-autonym="Монгол" data-language-local-name="mongol" class="interlanguage-link-target"><span>Монгол</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Ruang_Hilbert" title="Ruang Hilbert — malaio" lang="ms" hreflang="ms" data-title="Ruang Hilbert" data-language-autonym="Bahasa Melayu" data-language-local-name="malaio" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Hilbertruimte" title="Hilbertruimte — neerlandês" lang="nl" hreflang="nl" data-title="Hilbertruimte" data-language-autonym="Nederlands" data-language-local-name="neerlandês" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Hilbertrom" title="Hilbertrom — norueguês nynorsk" lang="nn" hreflang="nn" data-title="Hilbertrom" data-language-autonym="Norsk nynorsk" data-language-local-name="norueguês nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Hilbert-rom" title="Hilbert-rom — norueguês bokmål" lang="nb" hreflang="nb" data-title="Hilbert-rom" data-language-autonym="Norsk bokmål" data-language-local-name="norueguês bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-pa mw-list-item"><a href="https://pa.wikipedia.org/wiki/%E0%A8%B9%E0%A8%BF%E0%A8%B2%E0%A8%AC%E0%A8%B0%E0%A8%9F_%E0%A8%B8%E0%A8%AA%E0%A9%87%E0%A8%B8" title="ਹਿਲਬਰਟ ਸਪੇਸ — panjabi" lang="pa" hreflang="pa" data-title="ਹਿਲਬਰਟ ਸਪੇਸ" data-language-autonym="ਪੰਜਾਬੀ" data-language-local-name="panjabi" class="interlanguage-link-target"><span>ਪੰਜਾਬੀ</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Przestrze%C5%84_Hilberta" title="Przestrzeń Hilberta — polaco" lang="pl" hreflang="pl" data-title="Przestrzeń Hilberta" data-language-autonym="Polski" data-language-local-name="polaco" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pnb mw-list-item"><a href="https://pnb.wikipedia.org/wiki/%DB%81%D9%84%D8%A8%D8%B1%D9%B9_%D8%B3%D9%BE%DB%8C%D8%B3" title="ہلبرٹ سپیس — Western Punjabi" lang="pnb" hreflang="pnb" data-title="ہلبرٹ سپیس" data-language-autonym="پنجابی" data-language-local-name="Western Punjabi" class="interlanguage-link-target"><span>پنجابی</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Spa%C8%9Biu_Hilbert" title="Spațiu Hilbert — romeno" lang="ro" hreflang="ro" data-title="Spațiu Hilbert" data-language-autonym="Română" data-language-local-name="romeno" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%93%D0%B8%D0%BB%D1%8C%D0%B1%D0%B5%D1%80%D1%82%D0%BE%D0%B2%D0%BE_%D0%BF%D1%80%D0%BE%D1%81%D1%82%D1%80%D0%B0%D0%BD%D1%81%D1%82%D0%B2%D0%BE" title="Гильбертово пространство — russo" lang="ru" hreflang="ru" data-title="Гильбертово пространство" data-language-autonym="Русский" data-language-local-name="russo" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sco mw-list-item"><a href="https://sco.wikipedia.org/wiki/Hilbert_space" title="Hilbert space — scots" lang="sco" hreflang="sco" data-title="Hilbert space" data-language-autonym="Scots" data-language-local-name="scots" class="interlanguage-link-target"><span>Scots</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Hilbertov_prostor" title="Hilbertov prostor — servo-croata" lang="sh" hreflang="sh" data-title="Hilbertov prostor" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="servo-croata" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Hilbert_space" title="Hilbert space — Simple English" lang="en-simple" hreflang="en-simple" data-title="Hilbert space" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Hilbertov_priestor" title="Hilbertov priestor — eslovaco" lang="sk" hreflang="sk" data-title="Hilbertov priestor" data-language-autonym="Slovenčina" data-language-local-name="eslovaco" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Hilbertov_prostor" title="Hilbertov prostor — esloveno" lang="sl" hreflang="sl" data-title="Hilbertov prostor" data-language-autonym="Slovenščina" data-language-local-name="esloveno" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/Hap%C3%ABsira_e_Hilbertit" title="Hapësira e Hilbertit — albanês" lang="sq" hreflang="sq" data-title="Hapësira e Hilbertit" data-language-autonym="Shqip" data-language-local-name="albanês" class="interlanguage-link-target"><span>Shqip</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%A5%D0%B8%D0%BB%D0%B1%D0%B5%D1%80%D1%82%D0%BE%D0%B2_%D0%BF%D1%80%D0%BE%D1%81%D1%82%D0%BE%D1%80" title="Хилбертов простор — sérvio" lang="sr" hreflang="sr" data-title="Хилбертов простор" data-language-autonym="Српски / srpski" data-language-local-name="sérvio" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Hilbertrum" title="Hilbertrum — sueco" lang="sv" hreflang="sv" data-title="Hilbertrum" data-language-autonym="Svenska" data-language-local-name="sueco" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-tl mw-list-item"><a href="https://tl.wikipedia.org/wiki/Espasyong_Hilbert" title="Espasyong Hilbert — tagalo" lang="tl" hreflang="tl" data-title="Espasyong Hilbert" data-language-autonym="Tagalog" data-language-local-name="tagalo" class="interlanguage-link-target"><span>Tagalog</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Hilbert_uzay%C4%B1" title="Hilbert uzayı — turco" lang="tr" hreflang="tr" data-title="Hilbert uzayı" data-language-autonym="Türkçe" data-language-local-name="turco" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%93%D1%96%D0%BB%D1%8C%D0%B1%D0%B5%D1%80%D1%82%D1%96%D0%B2_%D0%BF%D1%80%D0%BE%D1%81%D1%82%D1%96%D1%80" title="Гільбертів простір — ucraniano" lang="uk" hreflang="uk" data-title="Гільбертів простір" data-language-autonym="Українська" data-language-local-name="ucraniano" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-uz mw-list-item"><a href="https://uz.wikipedia.org/wiki/Gilbert_fazosi" title="Gilbert fazosi — usbeque" lang="uz" hreflang="uz" data-title="Gilbert fazosi" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="usbeque" class="interlanguage-link-target"><span>Oʻzbekcha / ўзбекча</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Kh%C3%B4ng_gian_Hilbert" title="Không gian Hilbert — vietnamita" lang="vi" hreflang="vi" data-title="Không gian Hilbert" data-language-autonym="Tiếng Việt" data-language-local-name="vietnamita" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/%E5%B8%8C%E5%B0%94%E4%BC%AF%E7%89%B9%E7%A9%BA%E9%97%B4" title="希尔伯特空间 — wu" lang="wuu" hreflang="wuu" data-title="希尔伯特空间" data-language-autonym="吴语" data-language-local-name="wu" class="interlanguage-link-target"><span>吴语</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E5%B8%8C%E5%B0%94%E4%BC%AF%E7%89%B9%E7%A9%BA%E9%97%B4" title="希尔伯特空间 — chinês" lang="zh" hreflang="zh" data-title="希尔伯特空间" data-language-autonym="中文" data-language-local-name="chinês" class="interlanguage-link-target"><span>中文</span></a></li><li class="interlanguage-link interwiki-zh-classical mw-list-item"><a href="https://zh-classical.wikipedia.org/wiki/%E5%B8%8C%E7%88%BE%E4%BC%AF%E7%89%B9%E7%A9%BA%E9%96%93" title="希爾伯特空間 — Literary Chinese" lang="lzh" 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class="mw-content-ltr mw-parser-output" lang="pt" dir="ltr"><p>Na <a href="/wiki/Matem%C3%A1tica" title="Matemática">matemática</a>, um <b>espaço de Hilbert</b> é uma generalização do <a href="/wiki/Espa%C3%A7o_euclidiano" title="Espaço euclidiano">espaço euclidiano</a> que não precisa estar restrita a um número finito de dimensões. </p><p>É um <a href="/wiki/Espa%C3%A7o_vectorial" class="mw-redirect" title="Espaço vectorial">espaço vetorial</a> dotado de <a href="/wiki/Produto_interno" title="Produto interno">produto interno</a>, ou seja, com noções de distância e ângulos. Esse espaço obedece uma relação de <a href="/wiki/Espa%C3%A7o_completo" title="Espaço completo">completude</a>, que garante que os limites existem quando esperados, o que permite e facilita diversas definições da Análise. Os espaços de Hilbert permitem que, de certa maneira, noções intuitivas sejam aplicadas em <a href="/wiki/Espa%C3%A7o_funcional" title="Espaço funcional">espaços funcionais</a>. Por exemplo, com eles podemos generalizar os conceitos de <a href="/wiki/S%C3%A9ries_de_Fourier" class="mw-redirect" title="Séries de Fourier">séries de Fourier</a> em termos de <a href="/w/index.php?title=Polin%C3%B4mios_ortogonais&action=edit&redlink=1" class="new" title="Polinômios ortogonais (página não existe)">polinômios ortogonais</a>. Os espaços de Hilbert são de importância crucial para a <a href="/wiki/Mec%C3%A2nica_Qu%C3%A2ntica" class="mw-redirect" title="Mecânica Quântica">Mecânica Quântica</a>. </p><p>Espaços de Hilbert foram criados por <a href="/wiki/David_Hilbert" title="David Hilbert">David Hilbert</a>, que os estudou no contexto de equações integrais. <a href="/wiki/John_von_Neumann" title="John von Neumann">John von Neumann</a> criou a nomenclatura "der abstrakte Hilbertsche Raum" em seu famoso trabalho em <a href="/wiki/Operadores_Hermitianos" class="mw-redirect" title="Operadores Hermitianos">operadores Hermitianos</a> não limitados, publicado em <a href="/wiki/1929" title="1929">1929</a>. Talvez, John Von Neumann seja o matemático que melhor reconheceu a importância desse trabalho original. </p><p>Os elementos de espaço de Hilbert abstratos são chamados <i>vetores</i>. Em aplicações, eles são tipicamente sequências de <a href="/wiki/N%C3%BAmeros_complexos" class="mw-redirect" title="Números complexos">números complexos</a> ou <a href="/wiki/Fun%C3%A7%C3%A3o_(matem%C3%A1tica)" title="Função (matemática)">funções</a>. Em <a href="/wiki/Mec%C3%A2nica_Qu%C3%A2ntica" class="mw-redirect" title="Mecânica Quântica">Mecânica Quântica</a>, por exemplo, um sistema físico é descrito por um espaço de Hilbert complexo que contém os <a href="/w/index.php?title=Vetores_de_estado&action=edit&redlink=1" class="new" title="Vetores de estado (página não existe)">vetores de estado</a>, que contém todas as informações do sistema e complexidades multifocais. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Definição"><span id="Defini.C3.A7.C3.A3o"></span>Definição</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Espa%C3%A7o_de_Hilbert&veaction=edit&section=1" title="Editar secção: Definição" class="mw-editsection-visualeditor"><span>editar</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Espa%C3%A7o_de_Hilbert&action=edit&section=1" title="Editar código-fonte da secção: Definição"><span>editar 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.tmbox.mbox-small{clear:right;float:right;margin:4px 0 4px 1em;width:238px}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .tmbox{background-color:#2e2505}html.skin-theme-clientpref-night .mw-parser-output .tmbox-speedy{background-color:#310402}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .tmbox{background-color:#2e2505}html.skin-theme-clientpref-os .mw-parser-output .tmbox-speedy{background-color:#310402}}body.skin--responsive .mw-parser-output table.tmbox img{max-width:none!important}</style><table class="box-Sem_fontes plainlinks metadata ambox ambox-content ambox-Unreferenced" role="presentation"><tbody><tr><td class="mbox-image"><div style="width:52px"><span typeof="mw:File"><a href="/wiki/Ficheiro:Question_book.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/9/97/Question_book.svg/40px-Question_book.svg.png" decoding="async" width="40" height="32" 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Conteúdo não <a href="/wiki/Wikip%C3%A9dia:Verificabilidade" title="Wikipédia:Verificabilidade">verificável</a> pode ser removido.—<small><i>Encontre fontes:</i> <span class="plainlinks"><a rel="nofollow" class="external text" href="https://wikipedialibrary.wmflabs.org/">ABW</a>  •  <a rel="nofollow" class="external text" href="https://www.periodicos.capes.gov.br">CAPES</a>  •  <a rel="nofollow" class="external text" href="https://www.google.com/search?as_eq=wikipedia&as_epq=Espa%C3%A7o+de+Hilbert">Google</a> (<a rel="nofollow" class="external text" href="https://www.google.com/search?hl=pt&tbm=nws&q=Espa%C3%A7o+de+Hilbert&oq=Espa%C3%A7o+de+Hilbert">notícias</a> • <a rel="nofollow" class="external text" href="http://books.google.com/books?&as_brr=0&as_epq=Espa%C3%A7o+de+Hilbert">livros</a> • <a rel="nofollow" class="external text" href="https://scholar.google.com/scholar?hl=pt&q=Espa%C3%A7o+de+Hilbert">acadêmico</a>)</span></small></span> <small class="date-container"><i>(<span class="date">Julho de 2021</span>)</i></small></div></td></tr></tbody></table> <p>Seja <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \mathrm {H} }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">H</mi> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \mathrm {H} }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/32db8e791eaa12e32afc8fc1d60386643e43e315" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.743ex; height:2.176ex;" alt="{\displaystyle \mathrm {H} }"></span> um <a href="/wiki/Espa%C3%A7o_vetorial" title="Espaço vetorial">espaço vetorial</a> sobre um <a href="/wiki/Corpo_(matem%C3%A1tica)" title="Corpo (matemática)">corpo</a> <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \mathrm {K} }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">K</mi> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \mathrm {K} }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/715131ccf06a4d6af0074374757de835af3889e4" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.808ex; height:2.176ex;" alt="{\displaystyle \mathrm {K} }"></span> ( <a href="/wiki/N%C3%BAmeros_reais" class="mw-redirect" title="Números reais">Reais</a> ou <a href="/wiki/Numeros_complexos" class="mw-redirect" title="Numeros complexos">Complexos</a>) e <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \langle .,.\rangle :\mathrm {H} \rightarrow \mathrm {K} }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mo>.</mo> <mo>,</mo> <mo>.</mo> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo>:</mo> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">H</mi> </mrow> <mo stretchy="false">→<!-- → --></mo> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">K</mi> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \langle .,.\rangle :\mathrm {H} \rightarrow \mathrm {K} }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/835c4ab6985d351b417d0cac694e780891520fba" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:14.014ex; height:2.843ex;" alt="{\displaystyle \langle .,.\rangle :\mathrm {H} \rightarrow \mathrm {K} }"></span> um <a href="/wiki/Produto_interno" title="Produto interno">produto interno</a>, então <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \mathrm {H} }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">H</mi> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \mathrm {H} }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/32db8e791eaa12e32afc8fc1d60386643e43e315" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.743ex; height:2.176ex;" alt="{\displaystyle \mathrm {H} }"></span> é um espaço de Hilbert se for completo (<a href="/wiki/Espa%C3%A7o_de_Banach" title="Espaço de Banach">espaço de Banach</a>) com a <a href="/wiki/Norma_(matem%C3%A1tica)" title="Norma (matemática)">norma</a> induzida pelo produto interno<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span>[</span>1<span>]</span></a></sup>, isto é: </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \|x\|={\sqrt {\langle x,x\rangle }}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>,</mo> <mi>x</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> </msqrt> </mrow> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \|x\|={\sqrt {\langle x,x\rangle }}.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/cf3bc02e50c147bed811cfa18ee322665cb864bc" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:15.226ex; height:4.843ex;" alt="{\displaystyle \|x\|={\sqrt {\langle x,x\rangle }}.}"></span> </p> <div class="mw-heading mw-heading2"><h2 id="Norma_induzida_pelo_produto_interno">Norma induzida pelo produto interno</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Espa%C3%A7o_de_Hilbert&veaction=edit&section=2" title="Editar secção: Norma induzida pelo produto interno" class="mw-editsection-visualeditor"><span>editar</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Espa%C3%A7o_de_Hilbert&action=edit&section=2" title="Editar código-fonte da secção: Norma induzida pelo produto interno"><span>editar código-fonte</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r68971778"><table class="box-Sem_fontes plainlinks metadata ambox ambox-content ambox-Unreferenced" role="presentation"><tbody><tr><td class="mbox-image"><div style="width:52px"><span typeof="mw:File"><a href="/wiki/Ficheiro:Question_book.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/9/97/Question_book.svg/40px-Question_book.svg.png" decoding="async" width="40" height="32" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/97/Question_book.svg/60px-Question_book.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/97/Question_book.svg/80px-Question_book.svg.png 2x" data-file-width="252" data-file-height="199" /></a></span></div></td><td class="mbox-text"><div class="mbox-text-span">Esta seção <b>não cita <a href="/wiki/Wikip%C3%A9dia:Verificabilidade" title="Wikipédia:Verificabilidade">fontes confiáveis</a></b>.<span class="hide-when-compact"> Ajude a <a href="/wiki/Wikip%C3%A9dia:Livro_de_estilo/Cite_as_fontes" title="Wikipédia:Livro de estilo/Cite as fontes">inserir referências</a>. Conteúdo não <a href="/wiki/Wikip%C3%A9dia:Verificabilidade" title="Wikipédia:Verificabilidade">verificável</a> pode ser removido.—<small><i>Encontre fontes:</i> <span class="plainlinks"><a rel="nofollow" class="external text" href="https://wikipedialibrary.wmflabs.org/">ABW</a>  •  <a rel="nofollow" class="external text" href="https://www.periodicos.capes.gov.br">CAPES</a>  •  <a rel="nofollow" class="external text" href="https://www.google.com/search?as_eq=wikipedia&as_epq=Espa%C3%A7o+de+Hilbert">Google</a> (<a rel="nofollow" class="external text" href="https://www.google.com/search?hl=pt&tbm=nws&q=Espa%C3%A7o+de+Hilbert&oq=Espa%C3%A7o+de+Hilbert">notícias</a> • <a rel="nofollow" class="external text" href="http://books.google.com/books?&as_brr=0&as_epq=Espa%C3%A7o+de+Hilbert">livros</a> • <a rel="nofollow" class="external text" href="https://scholar.google.com/scholar?hl=pt&q=Espa%C3%A7o+de+Hilbert">acadêmico</a>)</span></small></span> <small class="date-container"><i>(<span class="date">Julho de 2021</span>)</i></small></div></td></tr></tbody></table> <p><sup id="cite_ref-:0_2-0" class="reference"><a href="#cite_note-:0-2"><span>[</span>2<span>]</span></a></sup> Seja E um <a href="/wiki/Espa%C3%A7o_vetorial" title="Espaço vetorial">espaço vetorial</a> sobre um <a href="/wiki/Corpo_(matem%C3%A1tica)" title="Corpo (matemática)">corpo</a> <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \mathrm {K} }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">K</mi> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \mathrm {K} }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/715131ccf06a4d6af0074374757de835af3889e4" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.808ex; height:2.176ex;" alt="{\displaystyle \mathrm {K} }"></span>, com <a href="/wiki/Produto_interno" title="Produto interno">produto interno</a>. A <a href="/wiki/Fun%C3%A7%C3%A3o_(matem%C3%A1tica)" title="Função (matemática)">função</a> <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert .\rVert :E\rightarrow K}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>.</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>:</mo> <mi>E</mi> <mo stretchy="false">→<!-- → --></mo> <mi>K</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert .\rVert :E\rightarrow K}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b9058bfd8bffa70e8d379d1cf860f2040a2e0a22" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:12.752ex; height:2.843ex;" alt="{\displaystyle \lVert .\rVert :E\rightarrow K}"></span> definida como: </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \|x\|={\sqrt {\langle x,x\rangle }},\forall x\in E}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <msqrt> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>,</mo> <mi>x</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> </msqrt> </mrow> <mo>,</mo> <mi mathvariant="normal">∀<!-- ∀ --></mi> <mi>x</mi> <mo>∈<!-- ∈ --></mo> <mi>E</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \|x\|={\sqrt {\langle x,x\rangle }},\forall x\in E}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/d6699ad176d88d1aa02c2bd9ca9ece8251ca45fa" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:22.852ex; height:4.843ex;" alt="{\displaystyle \|x\|={\sqrt {\langle x,x\rangle }},\forall x\in E}"></span> </p><p>é uma <a href="/wiki/Norma_(matem%C3%A1tica)" title="Norma (matemática)">norma</a> em E : </p><p>Demonstração: Vamos verificar as propriedades da norma. Note que as três primeiras propriedades seguem diretamente das propriedades do produto interno: </p><p>(N1) <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert x\rVert \geq 0}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>≥<!-- ≥ --></mo> <mn>0</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert x\rVert \geq 0}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/e5d31489b2d1aeb1c70ef12b0a13d7c4ab778308" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:7.916ex; height:2.843ex;" alt="{\displaystyle \lVert x\rVert \geq 0}"></span>: </p><p>(N2) <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert x\rVert =0\Longleftrightarrow x=0}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>=</mo> <mn>0</mn> <mo stretchy="false">⟺<!-- ⟺ --></mo> <mi>x</mi> <mo>=</mo> <mn>0</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert x\rVert =0\Longleftrightarrow x=0}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/2cf6ca30dc732c3f41fa993b0a5ae11b0f2363f0" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:19.113ex; height:2.843ex;" alt="{\displaystyle \lVert x\rVert =0\Longleftrightarrow x=0}"></span> </p><p>(N3) <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert ax\rVert =|a|\lVert x\rVert }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>a</mi> <mi>x</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> <mi>a</mi> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert ax\rVert =|a|\lVert x\rVert }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/2189c4fb83c67354f3f033fb07fb1b929e0a379d" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:14.161ex; height:2.843ex;" alt="{\displaystyle \lVert ax\rVert =|a|\lVert x\rVert }"></span>, para <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \forall a\in K}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi mathvariant="normal">∀<!-- ∀ --></mi> <mi>a</mi> <mo>∈<!-- ∈ --></mo> <mi>K</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \forall a\in K}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/42a880e90a16cf6faeb66c3153d5a90228a83cf2" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:7.429ex; height:2.176ex;" alt="{\displaystyle \forall a\in K}"></span> </p><p>Vamos mostrar a quarta propriedade da norma, a <a href="/wiki/Desigualdade_triangular" title="Desigualdade triangular">desigualdade triangular</a>: </p><p>(N4) <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert x+y\rVert \leq \lVert x\rVert +\lVert y\rVert }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>≤<!-- ≤ --></mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>+</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>y</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert x+y\rVert \leq \lVert x\rVert +\lVert y\rVert }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/2f4de362a3616a42c6b56e519f2e128b08a07b69" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:20.724ex; height:2.843ex;" alt="{\displaystyle \lVert x+y\rVert \leq \lVert x\rVert +\lVert y\rVert }"></span> </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert x+y\rVert ^{2}=\langle x+y,x+y\rangle ^{2}=\langle x,x\rangle +\langle x,y\rangle +\langle y,x\rangle +\langle y,y\rangle \Rightarrow }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <mo>,</mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>,</mo> <mi>x</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo>+</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo>+</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>y</mi> <mo>,</mo> <mi>x</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo>+</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>y</mi> <mo>,</mo> <mi>y</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo stretchy="false">⇒<!-- ⇒ --></mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert x+y\rVert ^{2}=\langle x+y,x+y\rangle ^{2}=\langle x,x\rangle +\langle x,y\rangle +\langle y,x\rangle +\langle y,y\rangle \Rightarrow }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/a995cf0189e05230c1bb63461de040bc175d7997" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:62.254ex; height:3.176ex;" alt="{\displaystyle \lVert x+y\rVert ^{2}=\langle x+y,x+y\rangle ^{2}=\langle x,x\rangle +\langle x,y\rangle +\langle y,x\rangle +\langle y,y\rangle \Rightarrow }"></span> </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert x+y\rVert ^{2}=\langle x+y,x+y\rangle ^{2}=\langle x,x\rangle +\langle x,y\rangle +{\overline {\langle x,y\rangle }}+\langle y,y\rangle \Rightarrow }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <mo>,</mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>,</mo> <mi>x</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo>+</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo>+</mo> <mrow class="MJX-TeXAtom-ORD"> <mover> <mrow> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> </mrow> <mo accent="false">¯<!-- ¯ --></mo> </mover> </mrow> <mo>+</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>y</mi> <mo>,</mo> <mi>y</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo stretchy="false">⇒<!-- ⇒ --></mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert x+y\rVert ^{2}=\langle x+y,x+y\rangle ^{2}=\langle x,x\rangle +\langle x,y\rangle +{\overline {\langle x,y\rangle }}+\langle y,y\rangle \Rightarrow }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/3f8430ccf5314a88c78d9e00bcf8161fa15527cb" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:62.369ex; height:3.676ex;" alt="{\displaystyle \lVert x+y\rVert ^{2}=\langle x+y,x+y\rangle ^{2}=\langle x,x\rangle +\langle x,y\rangle +{\overline {\langle x,y\rangle }}+\langle y,y\rangle \Rightarrow }"></span> </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert x+y\rVert ^{2}=\langle x+y,x+y\rangle ^{2}=\langle x,x\rangle +2Re(\langle x,y\rangle )+\langle y,y\rangle \Rightarrow }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <mo>,</mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>,</mo> <mi>x</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo>+</mo> <mn>2</mn> <mi>R</mi> <mi>e</mi> <mo stretchy="false">(</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo stretchy="false">)</mo> <mo>+</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>y</mi> <mo>,</mo> <mi>y</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo stretchy="false">⇒<!-- ⇒ --></mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert x+y\rVert ^{2}=\langle x+y,x+y\rangle ^{2}=\langle x,x\rangle +2Re(\langle x,y\rangle )+\langle y,y\rangle \Rightarrow }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/2d1e532b387c9cefc1b154b5e5ea83a36375399d" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:59.904ex; height:3.176ex;" alt="{\displaystyle \lVert x+y\rVert ^{2}=\langle x+y,x+y\rangle ^{2}=\langle x,x\rangle +2Re(\langle x,y\rangle )+\langle y,y\rangle \Rightarrow }"></span> </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert x+y\rVert ^{2}\leq \lVert x\rVert +2|\langle x,y\rangle |+\lVert y\rVert }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>≤<!-- ≤ --></mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>+</mo> <mn>2</mn> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">|</mo> </mrow> <mo>+</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>y</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert x+y\rVert ^{2}\leq \lVert x\rVert +2|\langle x,y\rangle |+\lVert y\rVert }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/5b1d91e63bd4940d708879cc6fd897f85eae4fca" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:32.404ex; height:3.176ex;" alt="{\displaystyle \lVert x+y\rVert ^{2}\leq \lVert x\rVert +2|\langle x,y\rangle |+\lVert y\rVert }"></span> </p><p>Pela desigualdade de <a href="/wiki/Desigualdade_de_Cauchy-Schwarz" title="Desigualdade de Cauchy-Schwarz">Cauchy-Schwartz</a> temos: </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert x+y\rVert ^{2}\leq \lVert x\rVert +2\lVert x,y\rVert +\lVert y\rVert \Rightarrow }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>≤<!-- ≤ --></mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>+</mo> <mn>2</mn> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>+</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>y</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo stretchy="false">⇒<!-- ⇒ --></mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert x+y\rVert ^{2}\leq \lVert x\rVert +2\lVert x,y\rVert +\lVert y\rVert \Rightarrow }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/eedc6e14efe3f1930fcaf86aa3ce1b22fc0fb5a9" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:34.594ex; height:3.176ex;" alt="{\displaystyle \lVert x+y\rVert ^{2}\leq \lVert x\rVert +2\lVert x,y\rVert +\lVert y\rVert \Rightarrow }"></span> </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert x+y\rVert ^{2}\leq (\lVert x\rVert +\lVert y\rVert )^{2}\Rightarrow }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>≤<!-- ≤ --></mo> <mo stretchy="false">(</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>+</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>y</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <msup> <mo stretchy="false">)</mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo stretchy="false">⇒<!-- ⇒ --></mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert x+y\rVert ^{2}\leq (\lVert x\rVert +\lVert y\rVert )^{2}\Rightarrow }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/87f19ebcdb8dfce7673ec2135a1312bec7729e30" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:27.611ex; height:3.176ex;" alt="{\displaystyle \lVert x+y\rVert ^{2}\leq (\lVert x\rVert +\lVert y\rVert )^{2}\Rightarrow }"></span> </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert x+y\rVert \leq \lVert x\rVert +\lVert y\rVert }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>≤<!-- ≤ --></mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>+</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>y</mi> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert x+y\rVert \leq \lVert x\rVert +\lVert y\rVert }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/2f4de362a3616a42c6b56e519f2e128b08a07b69" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:20.724ex; height:2.843ex;" alt="{\displaystyle \lVert x+y\rVert \leq \lVert x\rVert +\lVert y\rVert }"></span> </p><p>Logo <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert .\rVert :E\rightarrow K}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>.</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mo>:</mo> <mi>E</mi> <mo stretchy="false">→<!-- → --></mo> <mi>K</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert .\rVert :E\rightarrow K}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b9058bfd8bffa70e8d379d1cf860f2040a2e0a22" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:12.752ex; height:2.843ex;" alt="{\displaystyle \lVert .\rVert :E\rightarrow K}"></span> é uma norma. <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \blacksquare }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>◼<!-- ◼ --></mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \blacksquare }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/8733090f2d787d03101c3e16dc3f6404f0e7dd4c" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.808ex; height:2.176ex;" alt="{\displaystyle \blacksquare }"></span> </p> <div class="mw-heading mw-heading2"><h2 id="Lei_do_Paralelogramo">Lei do Paralelogramo</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Espa%C3%A7o_de_Hilbert&veaction=edit&section=3" title="Editar secção: Lei do Paralelogramo" class="mw-editsection-visualeditor"><span>editar</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Espa%C3%A7o_de_Hilbert&action=edit&section=3" title="Editar código-fonte da secção: Lei do Paralelogramo"><span>editar código-fonte</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r68971778"><table class="box-Sem_fontes plainlinks metadata ambox ambox-content ambox-Unreferenced" role="presentation"><tbody><tr><td class="mbox-image"><div style="width:52px"><span typeof="mw:File"><a href="/wiki/Ficheiro:Question_book.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/9/97/Question_book.svg/40px-Question_book.svg.png" decoding="async" width="40" height="32" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/97/Question_book.svg/60px-Question_book.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/97/Question_book.svg/80px-Question_book.svg.png 2x" data-file-width="252" data-file-height="199" /></a></span></div></td><td class="mbox-text"><div class="mbox-text-span">Esta seção <b>não cita <a href="/wiki/Wikip%C3%A9dia:Verificabilidade" title="Wikipédia:Verificabilidade">fontes confiáveis</a></b>.<span class="hide-when-compact"> Ajude a <a href="/wiki/Wikip%C3%A9dia:Livro_de_estilo/Cite_as_fontes" title="Wikipédia:Livro de estilo/Cite as fontes">inserir referências</a>. Conteúdo não <a href="/wiki/Wikip%C3%A9dia:Verificabilidade" title="Wikipédia:Verificabilidade">verificável</a> pode ser removido.—<small><i>Encontre fontes:</i> <span class="plainlinks"><a rel="nofollow" class="external text" href="https://wikipedialibrary.wmflabs.org/">ABW</a>  •  <a rel="nofollow" class="external text" href="https://www.periodicos.capes.gov.br">CAPES</a>  •  <a rel="nofollow" class="external text" href="https://www.google.com/search?as_eq=wikipedia&as_epq=Espa%C3%A7o+de+Hilbert">Google</a> (<a rel="nofollow" class="external text" href="https://www.google.com/search?hl=pt&tbm=nws&q=Espa%C3%A7o+de+Hilbert&oq=Espa%C3%A7o+de+Hilbert">notícias</a> • <a rel="nofollow" class="external text" href="http://books.google.com/books?&as_brr=0&as_epq=Espa%C3%A7o+de+Hilbert">livros</a> • <a rel="nofollow" class="external text" href="https://scholar.google.com/scholar?hl=pt&q=Espa%C3%A7o+de+Hilbert">acadêmico</a>)</span></small></span> <small class="date-container"><i>(<span class="date">Julho de 2021</span>)</i></small></div></td></tr></tbody></table> <p>Vimos que todo <a href="/wiki/Produto_interno" title="Produto interno">produto interno</a> pode induzir uma <a href="/wiki/Norma_(matem%C3%A1tica)" title="Norma (matemática)">norma</a>, no entanto fica a pergunta: "Toda <a href="/wiki/Norma_(matem%C3%A1tica)" title="Norma (matemática)">norma</a> é induzida por um <a href="/wiki/Produto_interno" title="Produto interno">produto interno</a>?" </p><p>A contrapositiva da proposição que segue nos permite verificar se uma <a href="/wiki/Norma_(matem%C3%A1tica)" title="Norma (matemática)">norma</a> é induzida por um <a href="/wiki/Produto_interno" title="Produto interno">produto interno</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Proposição_[2]"><span id="Proposi.C3.A7.C3.A3o_.5B2.5D"></span>Proposição <sup id="cite_ref-:0_2-1" class="reference"><a href="#cite_note-:0-2"><span>[</span>2<span>]</span></a></sup></h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Espa%C3%A7o_de_Hilbert&veaction=edit&section=4" title="Editar secção: Proposição [2]" class="mw-editsection-visualeditor"><span>editar</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Espa%C3%A7o_de_Hilbert&action=edit&section=4" title="Editar código-fonte da secção: Proposição [2]"><span>editar código-fonte</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Seja <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle (E,\langle ,\rangle )}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo stretchy="false">(</mo> <mi>E</mi> <mo>,</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mo>,</mo> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle (E,\langle ,\rangle )}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/529ad210c0bbb1892765721e2bfe1d352f146908" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:7.462ex; height:2.843ex;" alt="{\displaystyle (E,\langle ,\rangle )}"></span> um <a href="/wiki/Espa%C3%A7o_vetorial" title="Espaço vetorial">espaço vetorial</a> com <a href="/wiki/Produto_interno" title="Produto interno">produto interno</a>, então a <a href="/wiki/Norma_(matem%C3%A1tica)" title="Norma (matemática)">norma</a> induzida pelo <a href="/wiki/Produto_interno" title="Produto interno">produto interno</a> satisfaz a Lei do <a href="/wiki/Paralelogramo" title="Paralelogramo">Paralelogramo</a>: </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \lVert x+y\rVert ^{2}+\lVert x-y\rVert ^{2}=2(\lVert x\rVert ^{2}+\lVert y\rVert ^{2})}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>+</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo>−<!-- − --></mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mn>2</mn> <mo stretchy="false">(</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>+</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \lVert x+y\rVert ^{2}+\lVert x-y\rVert ^{2}=2(\lVert x\rVert ^{2}+\lVert y\rVert ^{2})}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/4d8f156e6b11e407e194e66c50752420348a80e6" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:38.404ex; height:3.176ex;" alt="{\displaystyle \lVert x+y\rVert ^{2}+\lVert x-y\rVert ^{2}=2(\lVert x\rVert ^{2}+\lVert y\rVert ^{2})}"></span> </p><p>Demonstração: </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\begin{cases}\lVert x+y\rVert ^{2}=\lVert x\rVert ^{2}+\langle x,y\rangle +\langle y,x\rangle +\lVert y\rVert ^{2}\\\lVert x-y\rVert ^{2}=\lVert x\rVert ^{2}-\langle x,y\rangle -\langle y,x\rangle +\lVert y\rVert ^{2}\\\end{cases}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mrow> <mo>{</mo> <mtable columnalign="left left" rowspacing=".2em" columnspacing="1em" displaystyle="false"> <mtr> <mtd> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo>+</mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>+</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo>+</mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>y</mi> <mo>,</mo> <mi>x</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo>+</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> </mtd> </mtr> <mtr> <mtd> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <mo>−<!-- − --></mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>=</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>x</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>−<!-- − --></mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>x</mi> <mo>,</mo> <mi>y</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo>−<!-- − --></mo> <mo fence="false" stretchy="false">⟨<!-- ⟨ --></mo> <mi>y</mi> <mo>,</mo> <mi>x</mi> <mo fence="false" stretchy="false">⟩<!-- ⟩ --></mo> <mo>+</mo> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mi>y</mi> <msup> <mo fence="false" stretchy="false">‖<!-- ‖ --></mo> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> </mtd> </mtr> </mtable> <mo fence="true" stretchy="true" symmetric="true"></mo> </mrow> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\begin{cases}\lVert x+y\rVert ^{2}=\lVert x\rVert ^{2}+\langle x,y\rangle +\langle y,x\rangle +\lVert y\rVert ^{2}\\\lVert x-y\rVert ^{2}=\lVert x\rVert ^{2}-\langle x,y\rangle -\langle y,x\rangle +\lVert y\rVert ^{2}\\\end{cases}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/046bb0a53f8c25831a3d97b42173fe459045ed6e" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.505ex; width:42.719ex; height:6.176ex;" alt="{\displaystyle {\begin{cases}\lVert x+y\rVert ^{2}=\lVert x\rVert ^{2}+\langle x,y\rangle +\langle y,x\rangle +\lVert y\rVert ^{2}\\\lVert x-y\rVert ^{2}=\lVert x\rVert ^{2}-\langle x,y\rangle -\langle y,x\rangle +\lVert y\rVert ^{2}\\\end{cases}}}"></span> </p><p>Somando as equaçôes do sistema acima obtemos a Lei do Paralelogramo <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \blacksquare }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>◼<!-- ◼ --></mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \blacksquare }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/8733090f2d787d03101c3e16dc3f6404f0e7dd4c" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.808ex; height:2.176ex;" alt="{\displaystyle \blacksquare }"></span> </p> <div class="mw-heading mw-heading2"><h2 id="Ver_também"><span id="Ver_tamb.C3.A9m"></span>Ver também</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Espa%C3%A7o_de_Hilbert&veaction=edit&section=5" title="Editar secção: Ver também" class="mw-editsection-visualeditor"><span>editar</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Espa%C3%A7o_de_Hilbert&action=edit&section=5" title="Editar código-fonte da secção: Ver também"><span>editar código-fonte</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Fun%C3%A7%C3%A3o_afim" title="Função afim">Função afim</a></li> <li><a href="/wiki/Fun%C3%A7%C3%A3o_identidade" title="Função identidade">Função identidade</a></li> <li><a href="/wiki/Fun%C3%A7%C3%A3o_n%C3%A3o_expansiva" title="Função não expansiva">Função não expansiva</a></li> <li><a href="/wiki/Mapeamento_contrativo" title="Mapeamento contrativo">Mapeamento contrativo</a></li> <li><a href="/wiki/Transforma%C3%A7%C3%A3o_geom%C3%A9trica" title="Transformação geométrica">Transformação geométrica</a></li></ul> <h2 id="Referências" style="cursor: help;" title="Esta seção foi configurada para não ser editável diretamente. Edite a página toda ou a seção anterior em vez disso."><span id="Refer.C3.AAncias"></span>Referências</h2> <div class="reflist" style="list-style-type: decimal;"><div class="mw-references-wrap"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><a href="#cite_ref-1">↑</a></span> <span class="reference-text"><cite class="citation book">Botelho, Geraldo (2015). <i>Fundamentos de Análise Funcional</i>. Rio de Janeiro: Sociedade Brasileira de Matematica (SBM</cite><span title="ctx_ver=Z39.88-2004&rfr_id=info%3Asid%2Fpt.wikipedia.org%3AEspa%C3%A7o+de+Hilbert&rft.aufirst=Geraldo&rft.aulast=Botelho&rft.btitle=Fundamentos+de+An%C3%A1lise+Funcional&rft.date=2015&rft.genre=book&rft.place=Rio+de+Janeiro&rft.pub=Sociedade+Brasileira+de+Matematica+%28SBM&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook" class="Z3988"><span style="display:none;"> </span></span></span> </li> <li id="cite_note-:0-2"><span class="mw-cite-backlink">↑ <sup><i><b><a href="#cite_ref-:0_2-0">a</a></b></i></sup> <sup><i><b><a href="#cite_ref-:0_2-1">b</a></b></i></sup></span> <span class="reference-text"><cite class="citation book">Kreyzig, Erwin (1978). <i>Introductory Functional Analysis with Applications</i>. [S.l.: s.n.]</cite><span title="ctx_ver=Z39.88-2004&rfr_id=info%3Asid%2Fpt.wikipedia.org%3AEspa%C3%A7o+de+Hilbert&rft.aufirst=Erwin&rft.aulast=Kreyzig&rft.btitle=Introductory+Functional+Analysis+with+Applications&rft.date=1978&rft.genre=book&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook" class="Z3988"><span style="display:none;"> </span></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="Bibliografia">Bibliografia</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Espa%C3%A7o_de_Hilbert&veaction=edit&section=6" title="Editar secção: Bibliografia" class="mw-editsection-visualeditor"><span>editar</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Espa%C3%A7o_de_Hilbert&action=edit&section=6" title="Editar código-fonte da secção: Bibliografia"><span>editar código-fonte</span></a><span class="mw-editsection-bracket">]</span></span></div> <ol><li>Botelho, Geraldo. Fundamentos de Análise Funcional, 2<sup>a</sup> edição, Rio de Janeiro, 2015, Sociedade Brasileira de Matemática (SBM);</li> <li>Coelho, Flávio Ulhoa. Um Curso de Álgebra Linear, 2<sup>a</sup> edição, São Paulo, 2013, Editora da Universidade de São Paulo (EDUSP);</li> <li>Kreyzig, Erwin. Introductory Functional Analysis with Applications, 1978.</li></ol> <style data-mw-deduplicate="TemplateStyles:r69328899">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:0 auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style><div role="navigation" class="navbox" aria-labelledby="Tópicos_principais_sobre_álgebra" style="padding:3px"><table class="nowraplinks hlist collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div class="plainlinks hlist navbar mini"><ul><li class="nv-ver"><a href="/wiki/Predefini%C3%A7%C3%A3o:%C3%81lgebra" title="Predefinição:Álgebra"><abbr title="Ver esta predefinição" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; 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class="vector-sticky-header-icons"> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-talk-sticky-header" tabindex="-1" data-event-name="talk-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbles mw-ui-icon-wikimedia-speechBubbles"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-subject-sticky-header" tabindex="-1" data-event-name="subject-sticky-header"><span class="vector-icon mw-ui-icon-article mw-ui-icon-wikimedia-article"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-history-sticky-header" tabindex="-1" data-event-name="history-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-history 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