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,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIzMiIgaGVpZ2h0PSIzMiIgZmlsbD0ibm9uZSI+PHBhdGggZmlsbD0iI0IyMEYwMyIgZD0iTTE2IDNhMTMgMTMgMCAxIDAgMTMgMTNBMTMuMDE1IDEzLjAxNSAwIDAgMCAxNiAzbTAgMjRhMTEgMTEgMCAxIDEgMTEtMTEgMTEuMDEgMTEuMDEgMCAwIDEtMTEgMTEiLz48cGF0aCBmaWxsPSIjQjIwRjAzIiBkPSJNMTcuMDM4IDE4LjYxNUgxNC44N0wxNC41NjMgOS41aDIuNzgzem0tMS4wODQgMS40MjdxLjY2IDAgMS4wNTcuMzg4LjQwNy4zODkuNDA3Ljk5NCAwIC41OTYtLjQwNy45ODQtLjM5Ny4zOS0xLjA1Ny4zODktLjY1IDAtMS4wNTYtLjM4OS0uMzk4LS4zODktLjM5OC0uOTg0IDAtLjU5Ny4zOTgtLjk4NS40MDYtLjM5NyAxLjA1Ni0uMzk3Ii8+PC9zdmc+);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: '92e6353e7c256baa',cH: 'WHDC2zbwv6XZYWeGOmTbTB714gOKzfwRYvU0XjhtWsc-1744329671-1.2.1.1-y83ylM6dqyzwrUquuNzNVcDPs9U88xkCTeIAgbaOk1.6RxpljKk_M7bLiBrARmyh',cUPMDTk: "\/1175.94080?__cf_chl_tk=Q2jlMHotMRt3Qf_apY_R.mOuL1_gjZx8aXQ0K9I8SDU-1744329671-1.0.1.1-Dt4LiLTeTKuzwyZtCEjZNij30DJhKMxoXLzCfAtcWyU",cFPWv: 'b',cITimeS: '1744329671',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1175.94080?__cf_chl_f_tk=Q2jlMHotMRt3Qf_apY_R.mOuL1_gjZx8aXQ0K9I8SDU-1744329671-1.0.1.1-Dt4LiLTeTKuzwyZtCEjZNij30DJhKMxoXLzCfAtcWyU",md: "Gp.ClpVGx4KS6VYa7FCr18aYrdqQBGWYamNpYyoZYA8-1744329671-1.2.1.1-dWRIJJLMM9H1Q10kYj8LPZCVQ5_HgfebNhBWWirc65wvlAJF_7KXGg_LxAg6vo15FxkwNSOz7N71Ndq5BOv37UmXPk5TDY6yBM3KSri7_WOHcoo_j65JCAOj4cg3PLLiSROZOZeOm6CDWILKkugiZQiQhUpV1dJm8xRLajqIKrvTLja5UBVrAuqfMFS8XqeEkWaQz7IBTkr1SqbUY8Cs0n_xrYGFKjMWYLCsYX127S0utMO_UGErkpSAHOU8H9nVdKXP3RC8kVI6CBK.zaTQRWm84rte70pBfCL55kvLslqC1LFT6NT6BLTJq1NSSNFzqBLqInolw0NdNUGl8sXok9GmH75KmB86Yi4G_x_4RdN2P2y_gPzHWLQPd.swTmQq8kQQ6tpJRzw4B7UtPfMoD4HNksO2FwzcOvYOogyeNRzll2e_Oyz4u0X88SLEkLU02WApssZDC114kZkvt7s_5RIKWTtKLIf4fmB5Uv1b5cf5w0SrpYHEYa4YU2618Js5kq8cGnuY8iNmEyx_zuxWKelgTVgU1eOdIaeS22U4GJN1IPdIGkg79prT.t2wahIEwyrndaUt7QBbEoptVEf6e0_FeifUCue8PGPGlcU390rrWFQD1eDNIC1E6i05_7R8ffbI_0SqYJ.IW8SVYwTXBh09sRQc5EYLUOford.1HOZGvqJqY1FlbYWnznygGwXgokc4CHMa2mEA7cv3ioUQ1aO0tawGIqP0mDSwt2vAYmyb8Ic.ZiE52pWKzIXoh158xxDPdAFDK7tMNCl05UPqvHuR8RDCmmC6zQg6EBJAL14DIA7wtbnPZC1Afpl3wwZlQfLSlNud.QDvqj2yxYn1CZ3AJVSRdQKO.thvKgOXGfk133Cr2uqHSbvN7UMGsRVR8JtVlYY_wVkJFg_APZkXdTPHP92DeKn09S3qZQI7qgXbRt8fnJTRGX2SpUIWIl_1mtaAY4G8ogUnkU_IL9pjpT1gd5gPq7V1.t6Gl6KFPttZJ81dx5GKKJVct1BJvKbO7U9_c2XI5KPk0.6TNlfVSpqpdgvOgZFFzj1VuGuoVdbQzDeANu4JqVyLyb1z9NknKQOroiqGaVDoLn7iH24Aqj4U.LpsWsWwW3ai9Mk0nvTO1OUB.0XEtK5QFZB6bZy9Ivg36lt.JSrt61QqJijLAY45RVeQ3xQlGrdkf6uQb3cvuUzNy50aL2Zb2aIXrFaU",mdrd: "ho1F.qi16uHMmtBBle16NRXs3MoQweiQcUxBhxYNLWg-1744329671-1.2.1.1-Qz7g_JM1smxnwQn2qd8zak3yiAUa8E.nTZWTwXlojfCKaRNmSnLj9meItrAoIfbWkP3uo3is1Frq_rgKP9wR.b7jbPZaKyTKGSwKVs_cX6w5qkvPoPI_oKuB3u8XTA4pTpu4QJLtmNQewVCsTSTzvumKNhGiYqJYea8qmeQn3rtsql5IAzr6fplb5J9HkrA_VW7keLOalhTCjWGS20jWHnXhTYnnOvxPP.b55g2NUbN8vWpm881e8z0Kw_xZBYIzTtV19zdKAG75JN.ixafuxDd3Nw4NIyP272NBZlIzgRmQuF37Pm0hBhYmHZyEKWf5fqLb5PfpIAQLfpbJvpol7uxoq6r26q3zW9ZFZtEU3sfjFi.asl8Ld3KXl1.xwDUd1XEakfZITkrmpk47qHtbtXatSZEdZ_wIFPLIC8yQyfyI82ChqnSR3.XgFhk8IyK9ha3lUV7s.Xe3XtIUo1YLBTU1jatj1QTcBzVY_KY26ZTAQAF0wEn8y13gmGGkhnuyMMhEHbEXfI2vSbztYtoCnEtXQxuizk7HmG2mQbfOrLNsWcAQGjz9NqeqJNhekrpT35ZllGk_KYQpfjkSOPOJTKoWAsHcdThrmRQ8L79eaV.Z2mUSIqbbAhHpys_TO2zHagZ.dgdg9fcZb0YvjYpth867MFco0_Xfp6rYztRbHYdAsJYeBKRCAUiQ3bG56HUFSOx46ltIJVH9jixV0mjgwfYz09kR.O8OxfO01HWlG8Q.TG58_5bG2Dy.VCIDNfWcjte8Mz3iJnBTenAJSRRGLBZYfoWwRJeRp.21Zy6c1m_WhlXAYqVhm3CvFinphTFj1..CHWvAtNWmNf.731sEuny.5rK8wAOuFL.BIbGq88Y44Q7LpqZXYi.jy8PWgqjjf5piIVnJZfCqZ0SWgUVU6uk4TcFrFwDwZabaysdFgwepzQa.T93yrKu8AvDboDUJT1C5a8kofqmfZnFvQ_tKCy9JkA0LbobzCBOJZ66MXDQ0OOpIi9bA_Rqf_2k7gZhlkV.fTFuE8PdiqUnYr13vJ6GGE6bFvTHUgs5tR61Nn1_sjoMlntJGOJ.rm.OgDTE7HXCXC.R2RLNf3YiKOq6vi1mSSFoHzKtcQdNr.DmzPaM90mG8rcKlCRWNxSf4YJQZ4oC5qoTtD0Gva0Y4k6G0ASx5_rH4O6KaqBMSklM67OhykypBoCJOMfm.F4JgzYzFD9Ekqlu9LiqPl35vsgMqh.taJcnMmTbyZxaiaMQCpV580_VrGW56DkAHE92pn6IfGwRETTiTvn6yNtS052XbBwbiEHbmlCaG4F7XwW8Ab7_bSUH6WMic9glUC4MrFtbAqW7JcCXFzDBW7r3wjwqCsjOsYtZr0zcFZtHV0nDi_SvL4IGwdNQcFppa7j8hFOCUg4nI4tl9bmAYZLNgxOYjcb6vyBH9jhwubT6PSn4KQ4ME8b6zRBHnSYMckeUk5Yw9peM8NEVU2PdzCI.UA7E0gjyrQokKBjTkXgjb22T0Uv061VrwrB8ZiOrbFbyiBIbcUb_z3C5NDnjpUTnm2ANTUOvAeo1rlFvOmYJy9ipy5TqgcxGzTWv2CiTstf.h91IoK.LHvyeP89gfNicQ9c2Wquk1aq1WR3JMWh9KbxUVAIXG32lnK2Zmz_.mebmHyKjOMHmr.b8NoiW8rIkqfoB48zdtH_CsZbfj4.oHEA4aXf0oCrSYeX38E0PIpfPHIAYOVepcvdUGwr97WL8ZMjHRYeHihyhjAS7XghrmEhBB9t5wseKL8IuA.Vhfz4i9vxPibhX_e.FkJizbri4n8gADVADCNu1w0V9zbRSbSDUXtIRxG23U6p617GgdIFE6Uh7JfhjmBqpNqEE592LEBh59WPivXKiJED9nhU_OeGwXrcLPqWX4KjTG0BWihvUfAvy0.A25YsExlsctk1.PGgwBaGnkBFrP9h4uvf6FtDQxk0p9ffO.gb6WA6_Tq4byG2J6svSjNnsGvqdJz3TR.MEVpif1K685MC3aNUsv1LVp_c5sJY5JW9ZBlwkBU0Vxxm3T"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92e6353e7c256baa';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, "\/1175.94080?__cf_chl_rt_tk=Q2jlMHotMRt3Qf_apY_R.mOuL1_gjZx8aXQ0K9I8SDU-1744329671-1.0.1.1-Dt4LiLTeTKuzwyZtCEjZNij30DJhKMxoXLzCfAtcWyU" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>