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: '92d7c8c61baf8209',cH: 'F_ZXRhU45jwQla69fvhdOOgIuozKWSZBHg5TlB3hYo8-1744178427-1.2.1.1-CujN4pw0zYsQ0zNvkPy_FStqYL1uLWCgQIl2kgsTwTnQT2xumNQTHNU1rdf5ApiR',cUPMDTk: "\/0513.26003?__cf_chl_tk=jGiAPNTjTJ1ChB5c4dTdhDVQ00mvwu2Xa9IEWwhpplg-1744178427-1.0.1.1-dDvKLSXmpXS2q2kaHtNxLytkde8lIdQ0YnET9QGyir4",cFPWv: 'g',cITimeS: '1744178427',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/0513.26003?__cf_chl_f_tk=jGiAPNTjTJ1ChB5c4dTdhDVQ00mvwu2Xa9IEWwhpplg-1744178427-1.0.1.1-dDvKLSXmpXS2q2kaHtNxLytkde8lIdQ0YnET9QGyir4",md: "i3KdRnfjUM42szdrks9EuXZJaa32x7KwhSR.RwOXuGI-1744178427-1.2.1.1-Cy5JSyBUz2T6XSqp_5VLxZ_he8aHExTjN7KZsStDdY5uhFPPHJ2IsvlhgDQHNnbXjH8FReLr3jqzZOkn76CynAfYVduf2cLgAUOcxKJbWpZiTxN_ZpUlThtsK.Uag3AX6t._HeAWFYnmLZFBqZAQSa1RhvFz7JFAskrAOqfk0JpmjnnzLzSHoS62zWdbyAjgG4gJPHT71MWq_nYxhedmmXwQPWCfTE.NIdyXTzyUQX.AXKekWJZ3QINm1knmCf.9wOxojGNxQyA5k9dwWYbdrA7aRylvNGyVW1irCKkFegtpY7YGYv0C._BWApBknkav2JopxZK_mVNIS6Z92DaQncYwfsT8Ym1lNKQRvGMuFqBJ4xmClRg_k1Y9b7S2dtcm4O8i2XMSiEe2bdlsiKqMXLFhGuaCz0OzLCh6T6z2eydndT61Ca0z7Frj689Be9H9gncW55tcuVi8U_e15IhWAZz.WxkPDniPOHGQ6mwLwJDr3bSp8TQUunfRD1dTJNMv8eJO.HgseYRErTJRkE7Oiat5w5jGfeTjPk_6ckt1c4MZgpQfgM2UxuYcNPB3or9y9.55l75gXIpQhbh4hwcIjDSMhfYuzqebPQDqWtxoJL4hqj9uDihUY2GZIBNj4EardVHdyjrF2ZqFvZQp145i8MCZqj87EFqVi6GZFQzzpJQV5tvUdUzDNDlP385JPPlnh5cAwh5KtUUfP9uZG6S2UVcwO_eLbm7smH7IWgEk.th3M85Rxz7iIUWqtw3028jD27n7gL0jHkcFXbC86H.VRqbJKnw2Qityy7f2n6Uq7sxucrMEm8wcNwGJyI6yT_LWH_vDF5FDLJdTYHyyyqqKCHhFSfVSGvZ6eI7Yyyb3OUwLxV2qGWi5FYpCYKjNmxs7uncwR5DHMYKqflehh7qvR84oZ3qZqdKiUcEKOIm.rctWICDOqF24uy7fWpwGeMsLLwRKFLiIk3UqMz1DKuB1_CC1cPzZjihb2hhUeduwgndyXJms__RuIqbrZQHeczQsKIeTWRNpZLY6QoKaHkMfRI3_k0.Zh4BDn2pY1l09KQ9R5_SPLFAPYTOfBSft7Eyl6nDTBqJlTgUZ0YjgYqlJfMdwGTfLr5Xm6XeKHe9vBGhKPxvTAP9.cnCFxrrec1uSU2p4rpAb8fZ7PdlfmWTcgoCqLWdctawmtTQMGchAzCh9RRgxTh_ShWGTz2OoqWlt",mdrd: "RCUtQ7NFYsGthY7tSQN80RpGhyrdyo8CQ4JPggm1HjI-1744178427-1.2.1.1-KbssxDe_1lNnPK6f_A.AZZLLA.GgrINjfXbmg1t4A1IgQhNnEWgdOEMg5rGlvZwShPPoqG5G6uXvmMA8pQi6DimfrnQPgVjU2oHboIC8O2jNi_8GsNrX7DQ02ek14A2FsDS.jFNLNp7Vl0pce_9W8Tq5ccFMIZ5J6IkZgzxfoBXxcyM4rn_DyLOKfOd7Usvf8oQXCExlmkyrskAmRzfHiz3aLCV8woF2OmEkRsy8.e_QuM5xMkDUHYwdJHMb1kIsH5uQdZSnD7IxUczlUE9KzTcUE_ApxU9.e4TEbBeP_XEcR17zc78Atwj4S_fHZ7vPc_2FhjT7TMRaNaKEsbAMJeM.7FRqyDtaMQXgT5HT65CYQtuEDAzuPHaDJgdZ2gpIX0OfxhxDQGlbuOUx6HPx3B.nwKNhoQJO4L4m_Z8xxweNGlDkDT.IK6ohYZ58gNUssJfKwEzK3S_w7aF2iLh5rlbiU6wT1ptMacoIgV.JzJZ6SAG88G3Y2tgbuYskngM0Oe.FroVrcdYCPUR0GemqQG_cAX5CP01GEvWb3do9mYnn8ggs2h3LtwVf6B9L3Dg.zpbn8im2SxTGSSWZjm_PixDDIRAyJddq4Bg7u3_IBZ89d.7GboXW5Ha3MLghFQZ_V5.XOQvr.Nw1gXZWI7qS7EIzTeru4SUQbqC6Boj3XJbCClHO580Pqt_wHX6j3pOZP_ldRNnhmaALFHAjJOR1WPtY3A57bFDcXLi7aQFVAeqF501rHYJijPQvTKYwGjpwdxv.C6RvmEt9InnYKuEPqxQC2N4nP5eodjmHpvlYPSOAikvtVrQcJu54zOUjZNod4vGyjqKGi_u5H4cSaH.U2JEm8_U.0sIKIJsgxBNcKmrO8EQDri0mQBEANqyda6fDUS3hXQTteyrToNscDPpV.a7xDbzWIwElMA64Y6wE0UWcpKsYVNoLc6rgbsiJXohWBCVK7cJWlcSQuYkDo.t3pczTiUYJUf6ZI5UDj2CnATnMvvY53QVWMbi.paGCY5hn8ZV5z4ib9rJhIDTkuQoCW8J5AlpvIYartIutRX0h24Zlyzak3Be19r1APFaG27nM_FsUrUVTCWkOeMw6F0OCF4xdsGFNV6V3RJKo7unXJfOGa7uYZTs6w3b0C7ixC0sU2MtMWAR9R39661mE3iO91Zx08z3DhEGlF1KVBKVkFjx7SvDTjjXvKObtFcaemz6jjC.2B75FQs7y_bgFNKcyOGswwUUoscpuK4iTmT6GgvbXf3NPYCKTzIkw45tp83EsSxPRe4lZDPUpNfAt8hNB1K8RFrqto0ND6cwVifjm0.JZDNdaJTx.7K4Afx.TSIdAjAGDuONOaWZ19wJY12JUYccfzeXwv4hWh4jqFjUE1qPDtmAqEccGeg3wEQRucOeiQko_uZxPBxHdxszJf0tjfz9uFa9QIhvoK8MERpArRhuoCiB4SCR.4NhT.T.GTiUfk.6yn9dRXycQkIfV.DWLanRAWl3vqEkAn3j_XH..t26cIHUKbMBEW317OekTYL0hLpn12L0P2CbAPQ9BKxy.5a1BoUE81vesNk3qtah1bWzfwyaUHI3JP1JmuIuZPYYb.RrV_nUg7kKVLVqEBqQhWSUos8KkPmLArDgm.B1z_1zHPe_UP.qnWxPGMQg4F6T59HbyWrvKJG9IFgangb60y1R4_OIk8aovd1i83UnxU9LbC0n2qZSZd2_Yg8M9snUGeAVZk84QWmwysKvUgvWmmNnwoKtN9srWwzmQ.1MiFY3lFSyA9OS1GGC.2yIEfm6kbQYzIT8RRn4FZ3I_NCQV6SLCvtF5lecL.mR1Pt8Hnfe.Amq7cKdGOIqdJPTTZzzpcx_WuWowSh2t5Y5vtmdhskwbm7sc.eB6AIiEJZW58_c8cRFdCQIQXaTVbAJdO_58X0OfqVKueSPUHhJmetzGv6AldCUfFuFKJmRp1JGjOYn28vIN3lZAtB9fiq3c_HpmxE2UhSV6_W78SGnXf0hJpm1vyJlmfvVsQ_rjTe2Efg3ebSYgf3cP6jn7xHGJLwSF"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d7c8c61baf8209';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, "\/0513.26003?__cf_chl_rt_tk=jGiAPNTjTJ1ChB5c4dTdhDVQ00mvwu2Xa9IEWwhpplg-1744178427-1.0.1.1-dDvKLSXmpXS2q2kaHtNxLytkde8lIdQ0YnET9QGyir4" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>