CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="390"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "zbmath.org",cType: 'managed',cRay: '92d6afa8c84deba1',cH: 'pHKRsC6r05tj2aofrbxihSi7XHYj79ZG5XaQb.FFcqM-1744166913-1.2.1.1-ek5BFfODrrqN5wBKiBXXXAYxcz8nKrvDhcHQqIuamm9FrDn8cx1nN..pA5WvgQkg',cUPMDTk: "\/?q=rf%3A2510488&__cf_chl_tk=UOmcqGKUY2Zqx3c2e5uE0kB3JW447Oph7XSlTmEGrsc-1744166913-1.0.1.1-TRHutTL9HNxMu7OLQWPr3I6_aOTmiaif1v6tlku92sg",cFPWv: 'g',cITimeS: '1744166913',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/?q=rf%3A2510488&__cf_chl_f_tk=UOmcqGKUY2Zqx3c2e5uE0kB3JW447Oph7XSlTmEGrsc-1744166913-1.0.1.1-TRHutTL9HNxMu7OLQWPr3I6_aOTmiaif1v6tlku92sg",md: "i9IZX.tmycXDUWj_HfP3AvwfuEJZ_fmVERWghoDEzA4-1744166913-1.2.1.1-u8lZMTME9WMe5G01_J6oo0CUeTYqRP6lDIAb_Xdex_eVV5m2f9.j1dIL5FA9Iw85wI7Hc_d1YVkWCwG.Bx77AOtcAt28wa6uWtWn90S44lTZXDZmSB42nwZEdza4RS2M7fw3k.KNe8OsAfVPDWQACWZvVtZaLaCRJxB4HnW5rgNOY0GzIwSVgvUMBBpM0hhdpAKE3qVW5syIKgOJqj.UiPRbXU.65B7sXn9_PeElbbDl2029UBhfZjmMcSHtHC4E_aT3LvIqAj6z612HNuRWYBJvAKU3UrLqXwTSMZK1Nlw7EDnVPiWnqOBna4bNjEHIFW2bS9ZMaUxJy4Puj0yeUmxBnTmluOLZQz1Pwq2GdzfzfhhrDE5PMuyw1U6zg5h2gxKfUiODtwx3Xi3sX3N3HL5oITa22E9lzAwXuRI5XJBSWXJOFOPH0vV5PddOIW5wMp8oDWaqoByGjJjkF9fFPcvHMz_DkFgAlWmNwvn_hM6ws8a9IQl5I9qLxrcKcxfK0YQyQTsqT7QQ9PsEpUNbiUh2aq7qV5AWaJW4eICLAVvc8mqUVm6QSnaeNiOj7dn6GtZ_7uUJzm3QSurUZvbIKh_ejvnjIT_81F5qlwpnARjIayMohNtNT5If.9jlIgYTOlMeG9x9PXtU_tfKt1C9jzi5bjiQyc6fx4XnYH_9eUzh3DXjExlah3TsJTCD.NOqcBQxmzYpZu2kOOJY5LcoQN9G.0NRzuOUggLbLz5D1huIHx2cOk.S.Ntk6G9MqIMODHwLeZ1REFsxNDW0J_oKBRFf.1hjd7yVwFUYZuI.22mdLtk3q91JWvl1ZAQ1e7sVRDYtHEPrSk9NYr9RfQAaW8CCgHw4ujNb12xSespE7IdUB5A_cpRyPWYIiXJJYPKwgJ4JPsVN4APZzcWZTr.pL_Bt..cATkxIMcA3VmG_N7b9eYCowTwZAtib9NGEciJU0zML9etABUnuuTxBCV42ypoLrPuyHWo.4iuggZHy4jGb1yxePTXhIkB65JQuzH0be2ATpsE5.GsERrpbvtF0MKhxSRpD_dNGtmsbLv4i1l0Ac_p69f3UX67JrwAyyrrDK8jNKDZwIC8mBlx_3zBZWrOMphO9YqoN4AJOqT0L0_nI4M2dpLLgSxPBZekRtRUxNgifjSJzsbw.qgd.btjNtvfd6dc_rqs3O_zGsx6eQpGjGXSunnE5H4J90pBhHlud",mdrd: "hTWIR8uqaPZjltCL4T2zjQgK0R8XlF3eU_fEh0aOyz8-1744166913-1.2.1.1-U7loI09CBOQF7xQ7aKapEblwe6vCXi3Qo9q.QAOCmUZs3Qp.uqxi6VVZof88gq82IBCGhDP5.1uuChzMaWDuoIvgmLqk1LRkDhhGmO1jp_cdtGz22MCy.Pu7mJ3.dCEtqWWtLxNkp696qeKGkiKfi8312VO5zPGO5MFQeDo4MclsUSPb7Z9Bor8UCtXjC4_YPM6Gzw.saLopnRUy_7asC4tcXgP1SlqwKvHzTrrBwk74qTm1ygypYav6xeaTMAsy_.97TG0xVE6LLgbyb34XOQUgccHeZTyo_EgOpak3nTpfMBeq3Dksv_DbkRRjXhpLO089E5JtETOMz0RKTNgaUFYj.hR0jSg7dBEareb1i7No9SWu_OgYQI5mkXVvXF.ddCnr0R9bYJdAmfbC0oMUS0ECQf7VF3VYjbYYgDcXalGW7tT.VdXS_7EDgtcYjlnk1kX0x6Qqp5dt56F631E0fhQ23TsD.LMvGXTwNdODBQn0M.XE8tBCpUBuU1wX1kqtKjMIh61YbulW0lJvRpZ3JJeQ9XMSjYR8wwVih70jfOOyGIhuXXWlasYtAijx2OxYn_NPhV5ZWAnlAQ2YpuaNdulyI1HZdTqo5JVTETMNaDCK4MoQgsA5lXS6V4ueTwzJEbYCZnw3DpOmzYvX3zs71MsPl6LTHfnaOpiY697F7LHDTUoZyJQ8Kg4oucRLng.eqLPRXdGb1NvgosEl1OfG1tROVwK8qvi_AyllxZDLUkLxQBFoKWnTX.Oc8jzKyqi8itwozCZAOnR2nRVkDnXC733CsOhJSV7EJl_01G2k4zmtCuXgptIUMA1y2cDW3MNZw61PxdRQNywYu_DE0oiupKqhfJC.3cPPU75qc8ArIy.I4nVOUwRavtYW6s4yle.HTSt87VylcQz.Y4rrK2wpfm7jtBe8kzUKSJlXdiqWLGgOojjDwEXWS8OfLkvbiBycQYkWFwuxor_UEinjDo_Gk0R4CCwB_P34qkmZ.WH1dN_qU3UNEOYAr2jhzjEVcp1MhsThi37V4OwMfzmkbTZoiWA5TWD2l.U914Ly2IcTMLM8oyCJP25tdCkeA8FNRZMmUCbyGqaaUn6VuD9SpFopmMQNZ50z1IAPX9cGj4y70kuDwqeZTGMjLxbDmgzshjDs6_PW7H58upchlx2LE0UR5NJ5waZ39lRRmA0LQ9beQJav.p05AevciUBN2X3Jblwpk9x.nudedIMaQEwRHi_CRyWP2RdaDIJOCBSq274upvE_Lz1V9AcVNzuDbIIr0ymCkosI_RJNs9CKIhJOwD5570GjyuoFH.czv2v9b0aQV2GR3JtQhyGUgUJBAOQLeysA9TJWZiyfXPkxa0IvoXisUVZP6n9.7G56290MnFPByK0BmwMmdw.EqeTa8nIqNRurOYwmJfxh9ShajwWDLN5Tq6lDgnikxzfZyAxpTul2HUN4p95vxCrybmWa4sfO.wWaTUeZnOkDc2Ig6X3OQzRnAAURHz9hs_ca8PS3aeKV_yll2j7plDLVEmh0370QpVCSfqwNbOgTV.mTq89mPPuZ8p13wV09GpF1KvyqnXs.KSRYIMDzRKIu9C9wwPQdJk93cYh3EFo3PDxdgUXK98QpsT8eZMP2GdCCqUWWLl6IOEyl_2YNv.OZDrovz9oeiFbFethB4Pix0SiJAd0__8T3YNwoccYAUHljRvyM8mV9PaKmuuN4sweBkqZDGSJdkaOdJwoT7QD28U3vL98B7rbZK_0vVdazAVEd.aQlYvd9GhRA5D4r3TViUDByEVrkK8KUXLmNJQh_64MSVbUO2L8HHVT3.BYHch6WNAeQ8dZkD7p4JgIVRlxEOw8RElTs4ekCC1g0SWVwuA5lZKkz_S.8pxnh6RbGFkvQcApnvwvfZF1aZ57A31MJIcF62OGEM4QBD405NXVGh_A3aPUTDpj20NbdmWcpnShVA3Qk5ikdMpBVNx_To_ZhUres6QPjN_T913hnZkeC6kNVee8PH8lU6hX8x47Yv_WMdq1QYriVMm2NdEirYnyDdy1njiDMaigg"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d6afa8c84deba1';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/?q=rf%3A2510488&__cf_chl_rt_tk=UOmcqGKUY2Zqx3c2e5uE0kB3JW447Oph7XSlTmEGrsc-1744166913-1.0.1.1-TRHutTL9HNxMu7OLQWPr3I6_aOTmiaif1v6tlku92sg" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>