CINXE.COM

Just a moment...

<!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: '92dadbdd9a48f8ea',cH: 'VPpOlLnjJe8XH6ANvO73sl6I8_rNbY3pUFrMJVilq8c-1744210667-1.2.1.1-rJ38OtvF7y9Mlf4hyN7bUIfh1T49TLX.hnl1tPBCAH2A4Qz9OVRG.kwnNa7jhxzh',cUPMDTk: "\/1509.76015?__cf_chl_tk=FLN_yvZTiZAbwUtgjFMWTZX784pKXBvOsMAQ_tTzVCA-1744210667-1.0.1.1-TCYkDjUR4NHlMRBVR.14LmrEzLFum_AgfSRFyuDagKQ",cFPWv: 'g',cITimeS: '1744210667',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1509.76015?__cf_chl_f_tk=FLN_yvZTiZAbwUtgjFMWTZX784pKXBvOsMAQ_tTzVCA-1744210667-1.0.1.1-TCYkDjUR4NHlMRBVR.14LmrEzLFum_AgfSRFyuDagKQ",md: "SdgpbKiuksYzHxpzFGmfT6bxYJX87WFEAWHkRmfKEKU-1744210667-1.2.1.1-n4qkhxKBEgggoc.brWnKpg_ydeqgJT4hgFXMzJUg.7xWOwLv8aALmu7Y9Jn3.dKc1hbP8i9Qes2LHzFvoXf22RLAjCV12sejtoypxQmiXwaCQJmGblM6GMf7zADcF6wQwe.J9KE8ki.GAcWZJo2puJ60.FQAtsIxdY81lLI4OqpXQokb.YAGco7d2Tssl7js2NJLj4K0XhLc3TYqnYR5ncd6Aq6ugpZAigmAIsIJYU0zox5B8cgJx5uGLKimq9GJJnkQRdC7iAywVCXzlZnyzNaU.EEkUHceB.YHtMdTVXY9.jQAhoQo9VDFu3flSng_vRr.fYiTRKxrYsRkcZWhrUglMpeMnzVcRRhG2JkmMYzaSrZl0yyvQoAbNosAWAnJ958wLFFJcHPsfuzHozcTldEMiaPK.Jg5GghPSXqEv6IoXohzyhkTALMDY6dpwr676pn9l.eah8oGf7WpmAA_tsUlBYJrEqH2Hj4.m3Ls49VZu5neioV9kSgCzYxRUn4a1geaHqv9sXUmYtKZEGZBog0y_cdbbs0g_0msU53deYkOiSxu.bIuZCd6G5uIb4wJexhIm1M9UWJJ96iaSr4oWD5QHs1.teOYmE3NkzhbjIt3ghed_hzkEafNR59GJQsthMxu2SictACllKaWEwXLEki_SJkf_pM8AwCOqdqlR8i5Tb3.TJAjeIe54vVLYBcE1c2zr.NZfDGeHl5FMYeCYDIF6gBR81UZGaVsY.rMT8tXJWr1ilT1T7qpVlN27dBQfMcQLp71DJeTyJvgxZb4VmUEFoRqvGCxZ7FrRnP_CylvQ3Ax0DpU1Ik53k4Ypg4U33l6uEWHW1OgHKi7q1z3D32h_x5nM5UuQFrmM9HJToQaPUlW1dJKzEELa4urShfvb_nVBIhWETxwaoZ1zo6Rnmj1D3a.YH7O0WvttGY2RMsK4pzMQmRDQA9cB_AipTnYjyngnFozsNmCpiX7r_rNAsCc.co5u6iu2kFkeXkG17kST82.ZJBZigOA82F786MEwD5X7K0a2fL8XSqsi0VA.Qk_qqQq7HJYBWva.UNYJjEwjDdogk9tjID7IXixHRG_I_44hzmqjFO6tAsX8krYzmK7N0ufeyIfPgb8H_92zPBSPCAQ_VGQoS18wm10AWNSDWWzfIo0qM5dT7LWopKWcvMWk7Xd55eH3nueZ2dwTTj2Y14KnnUagT69L6VIkc8g",mdrd: "11DkPG9h0jhNVPH.8Yu9QDlLc1QbTDVuTdkBJApffrY-1744210667-1.2.1.1-xEJ.DT2Pirzc837E7Ih_EUsD66Jac2O3vn_b7S3bN2IAwxNGLBPko4MDHvwMcG.TAddbT0_cFzpgoFc9g9RRll6O32kAh78xJ9IOUriSFyK6Ar1B90XeYk4tyMaM.wwHY5rYowPs9KAP7rPWkhi1sGOfSMPK5jVsB7jPk5kU6pl3B6PiqMAjP2reIRCSYk0HaY7G9lWPVFVdQvacqFgtqv7hHMP0EqsL5kZjL1owvgmQPIAtshH61G.IaBLZIuLvciHU0Bd0uf1zy8AOQVEqzRdjNTwAkgU9lj06UP3yWNYfQmFcHFb_4rzBVWEpexw.31Oe5hLBA3A2l2hp3yDeZFZTL.H2VOdkxPSkY24_ItMPgAYbrzWBnavOFlGDGhsWfeY7R_IRM8MsMW.FS9oVVZljaUQWPDLTk2Jvflga6MDl2nnnrLoQRdcBJGNIy.7Pn9.OQ6hPVoIPi83XeZauNtnlsHsdZr_ZF8gSpYZaC_ReX4zEfmx7q6sNSbHWztziWty2wT0hvvB6QD7M3rzrDlFU9VXtyicn4FNXI.feXot7DqKfcw.m.ILn2jkN0abc_g7Dl.pEQAg0kEdFkvrrkW018q8ajNNL_poXZsggZOWgjZHGwnn4m_82A7g5IFiqbHnQU7NKYmgNXdk9cgRWqWFznFMBVByRgydJQ9MGdatMszJMDXsN6SjgyQGLb6cno0QwiEksGfFGdUGqrVRrtqp5h.yxI0CeA2MH4xzbY.WunQP8GRKD72mlQme_kRKkfqnLIZHJRgSaxLf8euWE.ok.rPMM3527UWHkinmc9I1PVspPkEM80XOinAeRk4IURtiiUiujK6JNkcLbHRKF0HyPftXRltkNWfseLPIYg0LoLxZhorD02fOzA64OpNmN3lqlJxadCSBhBzz5V296G_LMDA3Rdj1P6uvehtiGHqnyEa5uxBFITiete2aFpGdAd.177kV4LCcT6a9f6IKjZIZNexQs47nMw196USPHiHT5h_X.7H7c30mhUOR5IRgxC3jlc0cB9r6xJ4yxYr6UJy5mVDTEOrty99kGWT_ZYA6wWGJLa7V8wGzlQy7Io_iumTdXQ7PehqlzN7TaA5RleNSfO9nIS9tUc0PKHA8VJWDAyr8RiB02sscYIgErDSP3zKTwlGXUSQZ9qbywN1aKo7cfdEyliUe6YyWBdCvGlriFBozzQrrF869zcFY0b34I4p8wr70.SY7r_DaIh1eg4u89475rhuv.smwOssidt9ojPoBO_SqxM3.gWfQRGzT27_uWd_kb1WFBx42nrQjNLgFUjEqJUE8xJXCIHTy2lGET6kSBUl7UdbhLPpDGC_S1sopBl.bPCfZ8h0y3m6xYuYKKNC2yxjhV_7xdGlJtMr3hC3UjqCkWAKEUl.stTAWQW6v2ncdlhFXPo6GkYMmVVssIBpAvqZGOoLCLAhZVKzzPQuZzIICMCdlqGHxhl4GzPwOpZgw4jRraEqLwByaWigCzWD4_w_rupcVgx6rSXJ14lAWfumMwZg0jpRMnGkm59fadGWKgSCrLvD8lwSkrYDfVY_LL6r6f9RVO4Do.q2XLLeelrYQo_qc.dOWm.h_TkjGQCHz9sqCgi0s63.LpoyfsgnT3snEJD_OBvtizg2gvfMoTeyneTgPHD4FuR2780U.pAtoEGB9OBuBPOw.yNuEzlbOc542m8affi88qRIqd6PAIV722eHNdqcp7ySNOAM7t7jUeQnu_Eo6Wyvd54nS2M5hk.CPNQCQS.J6lQQ0xnYXARW2mtbw2xdWvF4YxR6FPVGcL.iTIIU5nhVaUFa._iSPZhIDWLILgNcFcYsfwv_0TleriflWF54MXgkjlxuC86Ad8cwk6mqdm1FO.pyQr07jNKM..bpmE5pyoLpyhTmUeq00b9JxOT6_Rr28ngzHZs6DzqDq7sqBZFUF2x21EqFZAXyoH9G4GJTwXs3dNSPqrnk46fkbTww1ZywsQ1pf84g0pszRFzlvPVt3kkT0X4oXeHWBfuflF_5nhXBM3jMEY3cPqZ00WI79Zefln9Fy_QkAJd07NcYWt4bfFmQ"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92dadbdd9a48f8ea';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, "\/1509.76015?__cf_chl_rt_tk=FLN_yvZTiZAbwUtgjFMWTZX784pKXBvOsMAQ_tTzVCA-1744210667-1.0.1.1-TCYkDjUR4NHlMRBVR.14LmrEzLFum_AgfSRFyuDagKQ" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>