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: '92e7e4bb0c206595',cH: 'JZ9cZ4ZBFuGj8.HbzDCd_rFkx8ulTEHjhqF8Gl02VPY-1744347345-1.2.1.1-B6USpLePFUw2CO2G6fv56kt9vJOKfqQtY8Knu11e9bilI1wnrrVqG2G1poXnok7c',cUPMDTk: "\/0486.01006?__cf_chl_tk=_E1Ue_GJLZo7iLNe5KleSVCaNctgnnHsYAsPvSNnuD8-1744347345-1.0.1.1-kEK.T.ahAgbi.hAZ44v9BBRQkSHIAsfdU9Rp.tq_5ps",cFPWv: 'b',cITimeS: '1744347345',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/0486.01006?__cf_chl_f_tk=_E1Ue_GJLZo7iLNe5KleSVCaNctgnnHsYAsPvSNnuD8-1744347345-1.0.1.1-kEK.T.ahAgbi.hAZ44v9BBRQkSHIAsfdU9Rp.tq_5ps",md: "e_DQ1BrKm9RsQnA1TAhlbIsk5QE1ZU7RIml.Hzwh9Qk-1744347345-1.2.1.1-.Dn.a8fT0baF6BGS3D72qCUdMbsDZbgmukz92NYw0yQyX77mWoPomglHO9U3kpUahgpHJqcyDDFwwww7BzIsI9tnyGcsylHNOaS9liym3cEUOcxxzLhHeoeP0z8NTgNo70OQugjldRX1xm86ij5mVAvZH_0_Ku9XAepn0cPAqG2zHonHFOSVdW.heVPaEuWUsq.VRlNWlmddHbuwy.ODko2uut9uCzJTwQSnKrL6_CXLwQPnfGNF9FAm5GA3KjRf5_okGp4eJgpbOljRHsX6ZtFtu4JYpSKdDux7HJA2kKTGuzZF4hkX2P7F9gnt1sdNxxkj0_ard0.k4D3Y4FOxvPOhBGNxaIiKn8hgVrcB4M.9OV6yh4uYfSVzdtTRlTdvJR27hovBM6aVq3SljkDPseBfnFFEvVf0aaJ4qHJSfeFK9DZFbEvz4mvCpUMmj8K933Ba.9e1Vt8GUPtQfWNE845TU..BGIFPx8ZB9bY1EG4_YOQaY_1uDvHEZm9rO56lrUJi8ryJkLYRuU9Dd474F9xm4bpn0Ii9tvX_adWJ903bIMwy7pYD68C2RWFvbouFaRJpIJ8qvTideDn2lsV_rCD_qtoG.BSn6wzhnmCEQUkp1586Q1DH0h5M7NvbsZyKnKiiUKozvxpgNYWN90iS52_SZ9eTykD_zO5sYJR1Xb5oBVBohnjLhxxsXZUTQmq4.rXaxFTwoxTcJ2a2ENoIQfudPEX.Q.H_3H4m4Wq85YesOu5FM8GfAp7PXDxCgZsPckGqUh214qt3FRy8DY5EIUpq2UR6Ryy9S8ypqOrtCtsl.S5j2Mej8XJOgp_b1JaD.V954JIKg.MDxVyoxvvjmlzcVVW4aozxrUjHEq1iZsxFobTfBiaIIy4QMLEpgIG1fI2ced1imAFOON6wv8zw0jwKUYDT7sFfXDSr3ERLTtUievED8uYurIyNWARJgojDtA9ClwrQ6SIOtk39b.TGIPIhB7UlQRgootxdw6UuiaAhJjSzZvefrV52cBtZTIcmaFqkM7X8d0SEGWR.fkWvuq2evIEAl2yy3I5LQWkmwcMVd2yNBijZWgg52SdC7U3yXDrgVWVy7C6auDFIK7quabcfJLuhX7jG5fgM3PWaPDrOdCWucLmxHOnxePw0svk8Bc4V4Sr_uEYYW9G9Nw7FtDzBhm63uO3OtwfgbGOPuthczsTCcR_C7cThIj3rYLj_",mdrd: "briqbhnYnRXzDBzU_gc.ZOILOI1HJI_oFHIuVH15FkQ-1744347345-1.2.1.1-SmgmHZ8kR0mhie3hXeO8hzGFH8U7WOrJ4WcpboCE4v.9ZKYyJgQJCS1E4J1i4J5wj3P6dbztIUJFYhyipM0cuHJP1VJcNBQJ3IH4fkq3rk_wZlxWljRyUHhCAtvg60z7VklMKUjzopJ5MuH5ujT8Yxe6hdhXVroYUnl4cvUtuMj0CrMgXnZuzZyBhLUL3R_N_UpY_Ld9GU.5FOZmwibUuuaN6hXvDlWolnkVAtTYLBqw8v13p_K3DgxviS_fEZm_hxyiq40D_nf.ezwOHJOwJwL6qa6YbpDR_AF3eljfnJNNzO0X5a.V4S.mJMX3SfRqxh_RaQZJKHfV9Evy9b5EWsh9wCKVaI0kf6mSYo3fUCfdk8L7GcXvYaXEld5oxIqMlNkdcKEyb3HNUl7G_q4A1rx__2F.KTsRdwafLQed7e7M8Vv78ndARUPuc3t43peWJNcGb5l9HP3A5pX5vZLDOFPxLwp0URYYq94Ziwr4R7QrmEm5xJ7Ekh9jSIg9SOKLYyfKjNOAQ5fdzz2g0BrU1C5k1ZtEIx.TZx.wP14qgJuFGjXIPodLWz1bqDftBYOVBB_Mnp7UcZv4hWMOg2FnDWOVxYMbuy3Ejv0WxF0fSSJBaoRGx1gF.HJrmhgSsOsp4kov7BP9.podx.8NicZtQTF7BPVPAbwJNaOm2RAUq7H51XaDLYF5f94iyyBgiqlHO5ZR0x9U66LjgcJLUf.0jS.8QWwJJcq2XpqghsjOM5a7LrsyhWNn79acaIbZTaKy3D_J2QBngqTkXPCdQkoOHvjxKOzttHgnM9xHrJphluRPl3AfTfvqQV1BTikPwN7Rm.tBAy3bpkBT8FVzspbJUX5RsCAkQ5LNcig06AobOzvXnMA_YVE8p3Rq2eaGBFS0FzklT9XdLsGxRlqnnMovBKHWQUauZeuIJ8qgMlMtTX8UvrAP0eTpA1ZRfWzcQhau0v7y1uN56g661TrpbIFdaQyY.mDJ8QCMhWQyXVYRZt0sNGEIg0FRhgWWqJM75ZzKrdPGGqsY5ejFql20quwHMoigWUWzQ54HfndJtDM8hddMPaR9zMgfKiKAvwWQOCRvfZtWOBTdnz6QyZ09i_xMeqInCeBQ6bhM9AGOHco.85eLyNXow_I_ZZcpAL_Y2IWqvM_PIZD1C6s7rXs7sz6Nd4DqnZYpYQeYmRxPGJ74YPKXZl.quqViCqn41kaPjl8d.c45NLcergXn2baAPd0m1pfLsQAMj6p0fv97M2Tf6kFViDd5EbUpTz7dl1ARE7VJrqYNUanpMYtfFao.sn2whflHi_yzdciLDnbhJylLuRlxbaVvfXkcOAzbrpt798k1JZT5iNB3rN2MfKPG3flFFe04fWV_EMA1.kaAId_TJKm3xgOjFgcTnVszSfdRbxnI1EkTlmicB35O5zzYYjT.FdIB5cpzvKiAycXrCCvOKEGqi5AfZQKrlKTiuBTDY.AqkbYP0gE2YT0rQmrymCZ0Xg39Kep4hQONg5qGSXqcpZi.JE_RS0XiyEjgc5Miwz8bYcsdfXCTEZkGtQECCbraH3LUyBy1Y6q6aCzFh0cuc2O2ZlVdtkattAE4MEoR006rqhVBhMC2bhSwfeG1sP9dGPaj02TVSBYzudvgNfRjXvEUT1DhrsT.KVh5X6ra4aaqW1cHVLlSYP0Zlm5I_iArSQXKPHyrLukrDTYR3r1_MRICvMZemNWLRoXKj9HE1MrWgyI4EhaCD7gpjK0_oQlxiedA0G5P0ZAII1wKIEa95PiH0hxMAvUbl2Zt29xNnk08l.5LPORNZ823L_ECew5jawDedYOC43g5.w9zYzM.sz0wBWzKS4Ev9DZMjyJ8op9vkBuGsnIfytWrbBTtpb2Zap50TqALNWNJ3wRkkpvY4FYy14uY3iMqCaiRzkM5oyMYi3YYzlbtCeAXtl1eA0b49FC9o7Bn3.8RSY2r0qnNkY5s.XVVzuQlXWbwDDviEKr7cm6uktA6EehHuB2K8O8nFLeNho0jJo0ax9HvF.9EVn.ybEpWL1w1h2ROeaR4WxWu"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92e7e4bb0c206595';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, "\/0486.01006?__cf_chl_rt_tk=_E1Ue_GJLZo7iLNe5KleSVCaNctgnnHsYAsPvSNnuD8-1744347345-1.0.1.1-kEK.T.ahAgbi.hAZ44v9BBRQkSHIAsfdU9Rp.tq_5ps" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>