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class="vector-dropdown-label-text">Mostra/Nascondi l'indice</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">MathWorld</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="Vai a una voce in un'altra lingua. Disponibile in 38 lingue" > <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-38" 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">38 lingue</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%85%D9%88%D9%82%D8%B9_%D9%85%D8%A7%D8%AB%D9%88%D9%88%D8%B1%D9%84%D8%AF" title="موقع ماثوورلد - arabo" lang="ar" hreflang="ar" data-title="موقع ماثوورلد" data-language-autonym="العربية" data-language-local-name="arabo" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/MathWorld" title="MathWorld - bulgaro" lang="bg" hreflang="bg" data-title="MathWorld" data-language-autonym="Български" data-language-local-name="bulgaro" 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%AE%E0%A7%8D%E0%A6%AF%E0%A6%BE%E0%A6%A5%E0%A6%93%E0%A6%AF%E0%A6%BC%E0%A6%BE%E0%A6%B0%E0%A7%8D%E0%A6%B2%E0%A7%8D%E0%A6%A1" title="ম্যাথওয়ার্ল্ড - bengalese" lang="bn" hreflang="bn" data-title="ম্যাথওয়ার্ল্ড" data-language-autonym="বাংলা" data-language-local-name="bengalese" 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/MathWorld" title="MathWorld - catalano" lang="ca" hreflang="ca" data-title="MathWorld" data-language-autonym="Català" data-language-local-name="catalano" 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/%D9%85%D8%A7%D8%AA%D9%88%DB%86%D8%B1%DA%B5%D8%AF" title="ماتوۆرڵد - curdo centrale" lang="ckb" hreflang="ckb" data-title="ماتوۆرڵد" data-language-autonym="کوردی" data-language-local-name="curdo centrale" 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/MathWorld" title="MathWorld - ceco" lang="cs" hreflang="cs" data-title="MathWorld" data-language-autonym="Čeština" data-language-local-name="ceco" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/MathWorld" title="MathWorld - tedesco" lang="de" hreflang="de" data-title="MathWorld" data-language-autonym="Deutsch" data-language-local-name="tedesco" 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/MathWorld" title="MathWorld - greco" lang="el" hreflang="el" data-title="MathWorld" data-language-autonym="Ελληνικά" data-language-local-name="greco" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-en mw-list-item"><a href="https://en.wikipedia.org/wiki/MathWorld" title="MathWorld - inglese" lang="en" hreflang="en" data-title="MathWorld" data-language-autonym="English" data-language-local-name="inglese" 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/MathWorld" title="MathWorld - esperanto" lang="eo" hreflang="eo" data-title="MathWorld" 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/MathWorld" title="MathWorld - spagnolo" lang="es" hreflang="es" data-title="MathWorld" data-language-autonym="Español" data-language-local-name="spagnolo" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/MathWorld" title="MathWorld - basco" lang="eu" hreflang="eu" data-title="MathWorld" 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%85%D8%AB%E2%80%8C%D9%88%D8%B1%D9%84%D8%AF" title="مث‌ورلد - persiano" lang="fa" hreflang="fa" data-title="مث‌ورلد" data-language-autonym="فارسی" data-language-local-name="persiano" 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/MathWorld" title="MathWorld - finlandese" lang="fi" hreflang="fi" data-title="MathWorld" data-language-autonym="Suomi" data-language-local-name="finlandese" 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/MathWorld" title="MathWorld - francese" lang="fr" hreflang="fr" data-title="MathWorld" data-language-autonym="Français" data-language-local-name="francese" 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/MathWorld" title="MathWorld - galiziano" lang="gl" hreflang="gl" data-title="MathWorld" data-language-autonym="Galego" data-language-local-name="galiziano" 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/MathWorld" title="MathWorld - ebraico" lang="he" hreflang="he" data-title="MathWorld" data-language-autonym="עברית" data-language-local-name="ebraico" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%AE%E0%A5%88%E0%A4%A5%E0%A4%B5%E0%A4%B0%E0%A5%8D%E0%A4%B2%E0%A5%8D%E0%A4%A1" title="मैथवर्ल्ड - hindi" lang="hi" hreflang="hi" data-title="मैथवर्ल्ड" data-language-autonym="हिन्दी" data-language-local-name="hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/MathWorld" title="MathWorld - ungherese" lang="hu" hreflang="hu" data-title="MathWorld" data-language-autonym="Magyar" data-language-local-name="ungherese" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/MathWorld" title="MathWorld - indonesiano" lang="id" hreflang="id" data-title="MathWorld" data-language-autonym="Bahasa Indonesia" data-language-local-name="indonesiano" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/MathWorld" title="MathWorld - giapponese" lang="ja" hreflang="ja" data-title="MathWorld" data-language-autonym="日本語" data-language-local-name="giapponese" 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/%EB%A7%A4%EC%8A%A4%EC%9B%94%EB%93%9C" title="매스월드 - coreano" lang="ko" hreflang="ko" data-title="매스월드" data-language-autonym="한국어" data-language-local-name="coreano" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/MathWorld" title="MathWorld - macedone" lang="mk" hreflang="mk" data-title="MathWorld" data-language-autonym="Македонски" data-language-local-name="macedone" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/MathWorld" title="MathWorld - malese" lang="ms" hreflang="ms" data-title="MathWorld" data-language-autonym="Bahasa Melayu" data-language-local-name="malese" 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/MathWorld" title="MathWorld - olandese" lang="nl" hreflang="nl" data-title="MathWorld" data-language-autonym="Nederlands" data-language-local-name="olandese" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/MathWorld" title="MathWorld - norvegese bokmål" lang="nb" hreflang="nb" data-title="MathWorld" data-language-autonym="Norsk bokmål" data-language-local-name="norvegese bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/MathWorld" title="MathWorld - polacco" lang="pl" hreflang="pl" data-title="MathWorld" data-language-autonym="Polski" data-language-local-name="polacco" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/MathWorld" title="MathWorld - portoghese" lang="pt" hreflang="pt" data-title="MathWorld" data-language-autonym="Português" data-language-local-name="portoghese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/MathWorld" title="MathWorld - rumeno" lang="ro" hreflang="ro" data-title="MathWorld" data-language-autonym="Română" data-language-local-name="rumeno" 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/MathWorld" title="MathWorld - russo" lang="ru" hreflang="ru" data-title="MathWorld" data-language-autonym="Русский" data-language-local-name="russo" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/MathWorld" title="MathWorld - sloveno" lang="sl" hreflang="sl" data-title="MathWorld" data-language-autonym="Slovenščina" data-language-local-name="sloveno" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-su mw-list-item"><a href="https://su.wikipedia.org/wiki/MathWorld" title="MathWorld - sundanese" lang="su" hreflang="su" data-title="MathWorld" data-language-autonym="Sunda" data-language-local-name="sundanese" class="interlanguage-link-target"><span>Sunda</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Mathworld" title="Mathworld - svedese" lang="sv" hreflang="sv" data-title="Mathworld" data-language-autonym="Svenska" data-language-local-name="svedese" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B9%81%E0%B8%A1%E0%B8%97%E0%B9%80%E0%B8%A7%E0%B8%B4%E0%B8%A5%E0%B8%94%E0%B9%8C" title="แมทเวิลด์ - thailandese" lang="th" hreflang="th" data-title="แมทเวิลด์" data-language-autonym="ไทย" data-language-local-name="thailandese" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/MathWorld" title="MathWorld - turco" lang="tr" hreflang="tr" data-title="MathWorld" 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/MathWorld" title="MathWorld - ucraino" lang="uk" hreflang="uk" data-title="MathWorld" data-language-autonym="Українська" data-language-local-name="ucraino" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/MathWorld" title="MathWorld - vietnamita" lang="vi" hreflang="vi" data-title="MathWorld" 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-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/MathWorld" title="MathWorld - cinese" lang="zh" hreflang="zh" data-title="MathWorld" data-language-autonym="中文" data-language-local-name="cinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q719112#sitelinks-wikipedia" title="Modifica collegamenti interlinguistici" class="wbc-editpage">Modifica collegamenti</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespace"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul 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th{background-color:#dedede;font-size:116%;padding:.2em .4em;text-align:center}.mw-parser-output .sinottico_testo_centrale{text-align:center}</style><table class="infobox sinottico" summary="Tabella sinottica che riassume i principali dati del soggetto"><tbody><tr class="sinottico_testata"><th colspan="2">MathWorld<br /><span class="sinottico_sottotitolo"><a href="/wiki/Sito_web" title="Sito web">sito web</a></span></th></tr><tr><th><a href="/wiki/Uniform_Resource_Locator" title="Uniform Resource Locator">URL</a></th><td><span style="word-break: break-all;"><a rel="nofollow" class="external text" href="https://mathworld.wolfram.com">mathworld.wolfram.com</a></span> </td></tr><tr><th>Tipo di sito</th><td><a href="/wiki/Enciclopedia" title="Enciclopedia">Enciclopedia</a> online di <a href="/wiki/Matematica" title="Matematica">matematica</a> </td></tr><tr><th>Lingua</th><td><a href="/wiki/Lingua_inglese" title="Lingua inglese">Inglese</a> </td></tr><tr><th>Proprietario</th><td>Wolfram Research </td></tr><tr><th>Creato da</th><td><a href="/wiki/Eric_W._Weisstein" title="Eric W. Weisstein">Eric W. Weisstein</a> </td></tr><tr><th>Lancio</th><td>novembre 1999 </td></tr><tr><th>Stato attuale</th><td>Attivo </td></tr><tr><th><a href="/wiki/Slogan" title="Slogan">Slogan</a></th><td><i>the web's most extensive mathematics resource</i> </td></tr><tr><td class="sinottico_piede2 noprint nomobile metadata" colspan="2"><a href="https://www.wikidata.org/wiki/Q719112" class="extiw" title="d:Q719112"><span title="Modifica i dati della voce MathWorld su Wikidata">Modifica dati su Wikidata</span></a><b> ·</b> <a href="/wiki/Template:Sito_web/man" title="Template:Sito web/man"><span title="Manuale del template Sito web">Manuale</span></a></td></tr></tbody></table> <p><b>MathWorld</b> è un'opera enciclopedica on-line sulla <a href="/wiki/Matematica" title="Matematica">matematica</a> sponsorizzata dalla <a href="/w/index.php?title=Wolfram_Research&action=edit&redlink=1" class="new" title="Wolfram Research (la pagina non esiste)">Wolfram Research</a> Inc., una società nota per la creazione e sviluppo del programma informatico <i><a href="/wiki/Mathematica" title="Mathematica">Mathematica</a></i>. MathWorld viene anche parzialmente sostenuto da un finanziamento alla <a href="/wiki/Universit%C3%A0_dell%27Illinois_(Urbana-Champaign)" class="mw-redirect" title="Università dell'Illinois (Urbana-Champaign)">Università dell'Illinois (Urbana-Champaign)</a> da parte del progetto <a href="/w/index.php?title=National_Science_Digital_Library&action=edit&redlink=1" class="new" title="National Science Digital Library (la pagina non esiste)">National Science Digital Library</a> della <a href="/wiki/National_Science_Foundation" title="National Science Foundation">National Science Foundation</a>. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Storia">Storia</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=MathWorld&veaction=edit&section=1" title="Modifica la sezione Storia" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=MathWorld&action=edit&section=1" title="Edit section's source code: Storia"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Il sito nasce dai riassunti che <a href="/wiki/Eric_W._Weisstein" title="Eric W. Weisstein">Eric W. Weisstein</a>, il suo creatore, era solito scrivere mentre leggeva testi di matematica. Questi furono pubblicati on line per la prima volta nel <a href="/wiki/1995" title="1995">1995</a>, in un sito chiamato "Eric's Treasure Trove of Mathematics". In esso trovavano posto centinaia di pagine, in grado di coprire un'ampia gamma di argomenti matematici. Queste pagine, spesso curate a livello di enciclopedia o dizionario enciclopedico, formavano di gran lunga la migliore raccolta di risorse matematiche accessibili sul Web. Weisstein continuò a migliorare e correggere le voci tenendo conto di commenti e suggerimenti inviati dai lettori. </p><p>Nel <a href="/wiki/1998" title="1998">1998</a> il contenuto del sito è stato pubblicato a stampa e su <a href="/wiki/CD-ROM" title="CD-ROM">CD-ROM</a> dalla casa editrice <a href="/wiki/CRC_Press" title="CRC Press">CRC Press</a>, con la quale Weisstein aveva stipulato un contratto, con il titolo "CRC Concise Encyclopedia of Mathematics"; allo stesso tempo, l'accesso alla versione online gratuita divenne parziale. Le restrizioni di accesso furono eliminate quando Weisstein, nel <a href="/wiki/1999" title="1999">1999</a>, fu assunto da <a href="/w/index.php?title=Wolfram_Research&action=edit&redlink=1" class="new" title="Wolfram Research (la pagina non esiste)">Wolfram Research</a> Inc. (WRI) e spostò il sito (ora divenuto <i>MathWorld</i>) sui server del datore di lavoro. </p><p>Nel <a href="/wiki/2000" title="2000">2000</a> CRC Press citò in giudizio la WRI, il suo presidente <a href="/wiki/Stephen_Wolfram" title="Stephen Wolfram">Stephen Wolfram</a> e l'autore dei contenuti Eric Weisstein, accusandoli di aver violato il contratto e chiedendo che il contenuto di <i>MathWorld</i> rimanesse disponibile soltanto nella versione a stampa. Il sito fu oscurato dietro ingiunzione della corte giudicante finché il caso fu risolto per vie extragiudiziali con un accordo che prevedeva, tra l'altro, un pagamento di una cifra (non specificata) da parte della WRI, l'inserimento di una dichiarazione di copyright al fondo del sito web, e la concessione a CRC Press di ampi diritti sulle versioni a stampa di <i>MathWorld</i>. Risolta la controversia, il sito tornò di nuovo a essere accessibile al pubblico in modo gratuito. </p><p>L'oscuramento di MathWorld rese evidente quanto fosse ormai diventato diffuso, in campo matematico, l'utilizzo di risorse enciclopediche online, ed emerse l'utilità di una enciclopedia matematica online ad accesso libero. Fu avviato, pertanto, il progetto <i><a href="/wiki/PlanetMath" title="PlanetMath">PlanetMath</a></i>, che era teso a creare una nuova enciclopedia matematica libera; ancora oggi <a href="/wiki/PlanetMath" title="PlanetMath">PlanetMath</a> fornisce un'ampia raccolta di contenuti a carattere enciclopedico di argomento matematico. </p> <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=MathWorld&veaction=edit&section=2" title="Modifica la sezione Bibliografia" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=MathWorld&action=edit&section=2" title="Edit section's source code: Bibliografia"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><cite id="CITEREF''MCmicrocomputer''_208" class="citation pubblicazione" style="font-style:normal"> <a rel="nofollow" class="external text" href="https://archive.org/details/MC_microcomputer-208/page/n175?view=theater"><span style="font-style:italic;">MathWorld: enciclopedia online della matematica</span></a> (<span style="font-weight: bolder; font-size:80%"><abbr title="immagine in formato JPG">JPG</abbr></span>), in <span style="font-style:italic;"><a href="/wiki/MCmicrocomputer" title="MCmicrocomputer">MCmicrocomputer</a></span>, n. 208, Roma, Pluricom, luglio/agosto 2000, pp. 176-179, <a href="/wiki/ISSN" title="ISSN">ISSN</a> 1123-2714<span class="noprint plainlinks"> (<span title="Ricerca su WorldCat"><a rel="nofollow" class="external text" href="http://worldcat.org/issn/1123-2714&lang=it">WC</a></span> · <span title="Ricerca sul Catalogo Italiano dei Periodici"><a rel="nofollow" class="external text" href="https://acnpsearch.unibo.it/search?issn=1123-2714">ACNP</a></span>)</span>.</cite></li></ul> <div class="mw-heading mw-heading2"><h2 id="Voci_correlate">Voci correlate</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=MathWorld&veaction=edit&section=3" title="Modifica la sezione Voci correlate" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=MathWorld&action=edit&section=3" title="Edit section's source code: Voci correlate"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Mathematica" title="Mathematica">Mathematica</a></li> <li><a href="/wiki/PlanetMath" title="PlanetMath">PlanetMath</a></li> <li><a href="/w/index.php?title=ScienceWorld&action=edit&redlink=1" class="new" title="ScienceWorld (la pagina non esiste)">ScienceWorld</a></li> <li><a href="/wiki/Wolfram_Alpha" title="Wolfram Alpha">Wolfram Alpha</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="Collegamenti_esterni">Collegamenti esterni</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=MathWorld&veaction=edit&section=4" title="Modifica la sezione Collegamenti esterni" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=MathWorld&action=edit&section=4" title="Edit section's source code: Collegamenti esterni"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li class="mw-empty-elt"></li> <li><cite class="citation web" style="font-style:normal">(<span style="font-weight:bolder; font-size:80%"><abbr title="inglese">EN</abbr></span>) <a rel="nofollow" class="external text" href="https://mathworld.wolfram.com"><span style="font-style:italic;">Sito ufficiale</span></a>, su <span style="font-style:italic;">mathworld.wolfram.com</span>.</cite> <span class="mw-valign-text-top noprint" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q719112#P856" title="Modifica su Wikidata"><img alt="Modifica su Wikidata" src="//upload.wikimedia.org/wikipedia/commons/thumb/7/73/Blue_pencil.svg/10px-Blue_pencil.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/73/Blue_pencil.svg/15px-Blue_pencil.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/73/Blue_pencil.svg/20px-Blue_pencil.svg.png 2x" data-file-width="600" data-file-height="600" /></a></span></li> <li><cite class="citation web" style="font-style:normal">(<span style="font-weight:bolder; font-size:80%"><abbr title="inglese">EN</abbr></span>) <a rel="nofollow" class="external text" href="http://mathworld.wolfram.com/about/erics_commentary.html"><span style="font-style:italic;">Eric Weisstein's account of the suit</span></a>, su <span style="font-style:italic;">mathworld.wolfram.com</span>.</cite></li> <li><cite class="citation web" style="font-style:normal">(<span style="font-weight:bolder; font-size:80%"><abbr title="inglese">EN</abbr></span>) <a rel="nofollow" class="external text" href="https://planetmath.org/"><span style="font-style:italic;">PlanetMath</span></a>, su <span style="font-style:italic;">planetmath.org</span>.</cite></li></ul> <div class="noprint" style="width:100%; padding: 3px 0; display: flex; flex-wrap: wrap; row-gap: 4px; column-gap: 8px; box-sizing: border-box;"><div style="flex-basis: calc( 100% / 2 - 8px / 2 );"><style data-mw-deduplicate="TemplateStyles:r140555418">.mw-parser-output .itwiki-template-occhiello{width:100%;line-height:25px;border:1px solid #CCF;background-color:#F0EEFF;box-sizing:border-box}.mw-parser-output .itwiki-template-occhiello-progetto{background-color:#FAFAFA}@media screen{html.skin-theme-clientpref-night .mw-parser-output .itwiki-template-occhiello{background-color:#202122;border-color:#54595D}html.skin-theme-clientpref-night .mw-parser-output .itwiki-template-occhiello-progetto{background-color:#282929}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .itwiki-template-occhiello{background-color:#202122;border-color:#54595D}html.skin-theme-clientpref-os .mw-parser-output .itwiki-template-occhiello-progetto{background-color:#282929}}</style><div class="itwiki-template-occhiello"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Applications-internet.svg" class="mw-file-description" title="Internet"><img alt=" " src="//upload.wikimedia.org/wikipedia/commons/thumb/7/70/Applications-internet.svg/25px-Applications-internet.svg.png" decoding="async" width="25" height="25" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/70/Applications-internet.svg/38px-Applications-internet.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/70/Applications-internet.svg/50px-Applications-internet.svg.png 2x" data-file-width="48" data-file-height="48" /></a></span> <b><a href="/wiki/Portale:Internet" title="Portale:Internet">Portale Internet</a></b></div></div><div style="flex-basis: calc( 100% / 2 - 8px / 2 );"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r140555418" /><div class="itwiki-template-occhiello"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Crystal128-kmplot.svg" class="mw-file-description" title="Matematica"><img alt=" " src="//upload.wikimedia.org/wikipedia/commons/thumb/a/af/Crystal128-kmplot.svg/25px-Crystal128-kmplot.svg.png" decoding="async" width="25" height="25" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/af/Crystal128-kmplot.svg/38px-Crystal128-kmplot.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/af/Crystal128-kmplot.svg/50px-Crystal128-kmplot.svg.png 2x" data-file-width="245" data-file-height="244" /></a></span> <b><a href="/wiki/Portale:Matematica" title="Portale:Matematica">Portale Matematica</a></b></div></div></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?useformat=desktop&type=1x1&usesul3=0" alt="" width="1" height="1" style="border: none; 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