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: '92d8afd74fed880d',cH: 'ANmvRI3r._4WBI27947dA7zqfU0UlP1yqkT2MQl28D4-1744187892-1.2.1.1-pPq_lNfttR8lBbaCnnUN7uAJ2A6Xo0q_hJ0wZLoj7L1lmMuSczkhT.Gz1yH6hx_n',cUPMDTk: "\/?q=rf%3A6398370&__cf_chl_tk=Cqa8v7sfznholG6q23rM6niG7ad7GOc6VV2yBZy6njs-1744187892-1.0.1.1-Nk5qGimVTLxNX754d5RCrBUSPV1pRfjXlEDGKrAu8IA",cFPWv: 'g',cITimeS: '1744187892',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/?q=rf%3A6398370&__cf_chl_f_tk=Cqa8v7sfznholG6q23rM6niG7ad7GOc6VV2yBZy6njs-1744187892-1.0.1.1-Nk5qGimVTLxNX754d5RCrBUSPV1pRfjXlEDGKrAu8IA",md: "YN.inwgESEvAANHSzbwFiOt.gheEWthzwDA0M4xotfI-1744187892-1.2.1.1-e_1if9kUuLpjSdquL1mukre_XM3VAR9uFprGEjXDsCUa_hNQotSWW94ebYKg76b8k7QSLKWvHVVKlANNtYLE7XPLzMphu09e2jCSz.zejOL0BlKyJ0JE8.Hbe18IpIJL_H0qVys9zQ7Ux_9Bj.zTYlEJlz98oT7aRAIt2Q9sM1jQOtPA3OwdVZk7tIOQCY814EoFXQNU3szjVSNsrQC299W23m1r4R4DyH9JglD6kzUEwpoFRiQ_O20McUcuEE67WZ3eoDGkIrx47CUnZxasIAt1E2SU2xQo_Mw8Amhp7szXbgDW9ngC6qyw_RZ_Gyc1.G9eg3b_Pu_p.CH.e.8PUf_ZWjtuMAInMKVrUpZSdlOCH4ENAoTKbbzPAa6aD2tmWOOtM3JPzewDGAWi0RbrajDun.9NGQVRkhrQJfJIYIZxoI6pjXwaaTf_UOo2ROEWg1Nr9UAk0Vm2HMGa_rVGdXcL.U6HrelhMlOETmmJSlCoDqXUtEtG.v0tNw_Q8CIH0R56ZMF.4LG4RUPFqoBMFjWvAq4aolkXaKuL4GSDb8NejI1M1bslSiyLjlnnQztd0.hO7xkoG1YwcqLOSB8EcNubK1PjFI6rCfIwhVYYN69k3Y1k2iTVz8ZWf9JY8BsDyxjhZO84akzjPmzYLhta110NomBBlOwAXHEotfpf6SaWHPBEzJInU1tf8PS4Qv3Oc8Y.2Qff9ha5.y5SeaqU4rDh2pLB.hO0Q.htkSnaBT8Iz8x.Gs_nWID36cEN63kg53Z3Pc9ZD3PK7Qvpg5VwwC4bZ2fyZKE98y5tGMwTMZ.NfXHrb.z0Eu34ka0Qsj4jwzxq7lLaE5ZyjT9uQyDjibmARffuHUcHjPzAMhzZHuYuOT0Ylr1I13.kSsk529wjdSMwqKgX5UXYQHXabji9sXzN0Bz1XqlBKEEBdfgjKj5.M3nTvQ0JkyI1ZeJ3mq4so3i_K.QvGQJejWzelrp2pBAP.fPcQNvDswAZl1tJSJsZ_7eisQoLxTgd4tHVYc6saLT4zIsPjq1jDuUFkPgk8Cay6nUOQS99IywtXDjLSbUjLFDvsE1Lb9Y5e0hzi8lBK5s5rEoD.e5vsWQRk_G3TlUM.RSCIi7I2wdn2UJESb6.zYRxGrxCwZW_YqljUrT6KC9M0BxUcGFZVN0ARcisOw3o8E8Q0fgTNY7ahAsmjcYXjFVZbiup5RMAZzdgx_Eb",mdrd: "RjnSlu26yOqKL.0otb4_ZuVty2LUILLwInVJNaZMlDs-1744187892-1.2.1.1-Vwq0BsboTXw5CyYBiO3Rsnl9wX0cbW26H_Z9fFobcGF9o8P9VI6NuZsZzMKszPIPUKCJNLZw19K7.jEdnCWEYHMQC1s1uJ9oXTVpIu8UoW_YzckqxrWxPgaIkDScAIRGnOVVKPawOuaqssCpNDI05bqxfKqxpKSodkJeZzEjiuqpTe2Uqz18tMw9v6aIVBMVrtM4eUbKwtyJOWoutzJ1894PTSlpVGVkWlUIzzMPxMYWLy_jZzvAMsfEJU9ZZ_VfEdhEAqlzAonOegBl4YlfwWFrxzrYP3FLfAqUyErNob9.iZZQtsGMzeOzSzPOcdTkNXoa6RunGEP9VCDhWyni37ZSXBnGTFIRwES41bozEqeEl9xp.wR6bKLUPx3pAd9WZ0iLJ3wvHNwezrIjROeshBoR.SwBrVMuVq5tV_u8xAHlhs6bMxVfWVjztxGqQu1b6mXNkzc94z5jPGjq4vXtvXhEPlIdNVIrNKlyIIwlvDua6_Ca80mC.XfXZ757XutAJYoyGanqmxK.MwY8IVVW4DkV66efCuOp6289Y8kMp.YfK2X0KC5eHHmv3YPo6_9vpQ9xocXST04OTP0.M8cMTdVoQEoFkJbfMVQAdKQbSgKdL6iO12e07nDdDli4sQNgRf8FUOK0rr8dwkQic6Imrpwe6EU96G6J0xKIvm3idL7PWKG5izm4V_QyFnwe3ERU1lt2Xq_UPsp7i8WWqv5RT6Sa1RCSseClN2mxEv0ogiiUgwNMAOqZzVVnf8zLOXLbF2O.P_PiItZ9f9mGe3iOi2G0uxSBWIbdL_g7JAmnQaYrhEPWIF338bsU7D0YMSvq2nmjwFKsKaNd.xI0WnRsZANBzIri7D4MmzbZ4tTivLw7tjD20OT7faSYLE4d0YeFRcyzrB2TI1I22HVStE8_k9kcnzM1cS9sz8qKbyONZ5DrAdUaXPNHCsfs1zZk50tecWOs2.aoEAKYbmKMnYu9et.cda7tUDGayeqMHM.1LHpnpIMNYVYUxb08xdPnMZOJDEV3aWHX9xj.5i8Ykx3n6x1axxRXyuHLiTATIsFjrKXfcqUhtiSELQ.QNCPUOo0MaD9sg_.LRsjMymE6fEe5CrFsDw0.IZTCKKVVBFZI66gPtTtr5qT7qvhfLuoREmY.3htXsmFthipMCX4sqbJiNtCM9asq4Gkgr6Y.PK4RH0418tUnMU29qyrkUOb5dZ9TudF_H6FcpRil66QAsZNdGgwspf3mkwtM45UuX4fFxKZljJcpFjIp7QFv17ZPmJRJwA00gx_rQd8.a0AzEJspUZywIbfmLJq479g0c_b.CoX9xqUv_msi5djuO.D6XizBsMOZ9AzmmgFgpoLFkVXwNeTtNKme2_5H_m5SE6bZhpNmwJEBJ_qHBOpsVIwJrFVfkUZfRwTHEa7txw7DhuGiR4POp11uO8Cuuhm12XsUeBJDe2JkcbQbjnJrAvo5aipGX8m2SioBl4TF6J59lCbhSS3k78HqrSfbt4vjSHyQiJSneiBrkTNUN1LOjtdl3bDuQWvkyWJRXv.SRrwJAdPTutppUbq0E1CxMF_KoO_0MqE18GAq63UCeEOQycseu5jf3j4fPvSKt2ZGMu5ywnaLC0PnWJWrcuFfnlG0la_lrp5lsbc_R7_Ycqw7LzfJqqFNrBh0g._qGewZkeb9puRe8h4FMKfc37o9pBRzc9JCS0mJTP2FzzqXDR6jqbPX4YQ_aObZ2PXT7mCXy30osnRl8f5YN72k0WI44TLgq1eTZ5uE5mQIUDU1KdI.CqBc.WRDD.Pmn1ZeHA0lBkuXUlV3jnW7_9Zq.zGSP5.5p_ddiQHGXDGFjw.sn89WgQZwHK9vKCLeQ9xz2O1GbYUYeM5Xd7AQaqEZ1hlYu7xZFLnR0z4q.FPZX8JkQ90DewhwpNcfQcFnbpoJxedz2k.E6o9Sli8yBK_akr7bAbs9zDadll5aFHFitjHG2egBQiRvoEcPTIjiHFUvvaYvezak28dMi2Pvm.GwFPBmnEMSg_ZIl7eAjLRMuqolcw1bvtfNI80J"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d8afd74fed880d';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%3A6398370&__cf_chl_rt_tk=Cqa8v7sfznholG6q23rM6niG7ad7GOc6VV2yBZy6njs-1744187892-1.0.1.1-Nk5qGimVTLxNX754d5RCrBUSPV1pRfjXlEDGKrAu8IA" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>