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: '92d60fb95f53fe10',cH: 'nauHL_cImnsuttJP6tUkERaovbCNmhS9bAq7XPNJfd8-1744160362-1.2.1.1-2mrKIsmJ1Q7dXv8ltDszWUf148L6dxVlQDu.NcK6RSPblxKo75w7iE4uNyjW0_K2',cUPMDTk: "\/1166.34332?__cf_chl_tk=aryTf4p49VqTXaMsugXuOthaSaym7W8KcVK3oDPFdh0-1744160362-1.0.1.1-NcWL9LCGVzgHwPrEzqFPLY3PP0uUV2rr4fdAfKph5P4",cFPWv: 'g',cITimeS: '1744160362',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1166.34332?__cf_chl_f_tk=aryTf4p49VqTXaMsugXuOthaSaym7W8KcVK3oDPFdh0-1744160362-1.0.1.1-NcWL9LCGVzgHwPrEzqFPLY3PP0uUV2rr4fdAfKph5P4",md: "s1EvTfmUdQFTvqVXCYV8JsUGjCeDURhTQlKoBrvKriQ-1744160362-1.2.1.1-UX1fP28j21ewnQe27dtbRqjtUoTzQuOvpHnD6DHTNgk.ovDaypttBudxFHsaZPvHteOynatqXznQ28AyFgnNUA3vujDJ4akCdyRswMN1SGWKZrNs2bBv5.O3CFMOD8BdORq_Pe6EXAy8GOSKPZYNwGooRi3YqoRqG_TA7UeDCA1_v2ft6MY7q3febVLOfDcN2r0T4m1YvmCVtpRUNVxxt8a.z4ktBuLlTqrY0IYD31KQLxpkpApwUfWQ7d2irey34RuVJoJizUgSvUopdi68P0oh2cVexQTeKuHAipyRDcDEIp9AP_H1KYMMJ6f8XDjQEgna.DtERNV77vaLDU3XQRHWnRX4Z4ReXFKbZsE0usnFbgXOaWseK_GmIuxnLjnPg4GI1DoQbJ7xQTX7sNvuhgHjUCScMB2HsPsvb3sOI2T.ZPTweVqesnybfNym4OofDeKXfAV92qeqWq_NpXK6Si.OKM4qOwG7n1gKTH5i_Z0HO5B5U0Qm8SbiwMHuS5nmkQGl5FLfKlAt2AWHYbxRKrDnJIzXteH1gsNZt1hMBjewvfn8ZBGJ5dSbyf_19kNPKx1sMexNQiJIIGu09iT.EiFvfudD5Etltrcz9yR3EqC2YDKhKQn7dJcb7UGAqIvgNtpL9uHsNfzmvTyY561nj.8Lm26YgoqZBkHP7_SSV_ceSyECrX30.7sVVtDVvAm77Mr5mW3Ou2FcxGj6xttStkPHMhjalN1aCKim_1_6XuIj5085CKAKFj.2nuwUMQjKpUiFEa3it3uUIwUEHsUudjKmO2.cToDOhBEuzDJg4yGYfFdCEp9eEu5BYZ23KRnch0E9PeHEDNsEYH8tZGR8zhzflCi9sKxSLD9LA72wmvKR0ixJv9Kea5bTMCxTj0WevTQ1PriiUUkZasR5QmgdnJx6EMSZeTVNolCymdZB3S81qI3lsJ1RDlyT2CmFOzuWVu4Xrsc65Pme7cfvgtuZp9OdppYXPFz4a2b3DtgLS0Yx_KNq96tni.PZvNDa3FCRUC0FiUqR__WINVB1bedCohCb7Og0Jx56v_achUlA7hcs0shiKhsI2KsjrJzHjel31Kq7PxwtmetcdQCxcMQNq4E91S12d0qLQ_BEcZk8aZQlOqCUwjI6MSgIj5F3cV4yThC_gi5vNmYt4.ibvIrvewBNs9VIs7OroKkNuKRoDGY5_e58gU0aXwcBWKFpvHmd",mdrd: "PvHVKDrmt12hevQ_uGfRS9y6a_xzMoH1uyjgFQOt_rA-1744160362-1.2.1.1-vSqjmBN6LyDSHraNZCzBHd0hJtdT7xeYpSahVFBhUXfuMz5zrhi0x2PYU42CGBwgiHvi0tdJR1WuKyBuluBKrCi6YBr01zf0OrRqgNFka6amw9G5XIrPz8teAOwaYZAoyz5ZkS.moWYRhotKna3ORaRXtdEcKI.UDRv2BmkaG7aLnIn4Qq9VrokQp8VaeR7rc6EXh8tVGEhM3TFL6ki1LXRtnXHCQpz8bk.qDCTvr6QZyWGGcnwzJCbpwWXZOsTz9oWcnsRlLYO1.hI5tg8Oc5qqej.PTgEFSvskHHEkU3LtBE342avXIHa0PILOBfP6tOT38mW334oA2f8O3xWv4rjYE8BEwPp6.BB1nPDlQRMjlYN_QQiPsNdGX0jVQt1VCkk0v_ewfuv0undFOUmEsKK66xwUQYQY5sHY1eV9vMvcmJa793oW9V16bW76nWHdn6L0sk4RFMtEQ0VXLIOChB.sdoOdHN1iWdUso.GMvxZaYDRlHDgkdpJyNkE.B1cqjMaNgvHO7wG5Ijm3cPqJ.QX_55O2KQlUM76Z6teFIXTyLJKzUyVlDHeYH6Zgdqp5dwx7qskKTvsC_c5XeWE.m2HHpL7x3sctlBEkU23L2FCQ6tFmKlEoIEW3S9h_o9ekcEJrgGkeF_JTeQB.HFyb7.6fp8GnLvfIQZM8z7fPTNnnXdznY_BvI1fYI.WHMGlcvDyH.2o2.8bBH5nxUi2cNu4SBzvFibhR9Fa11V9AwzBsWSK2V5NYEsAQAHiH6QY6Mcg21o1zzX4dQz6t75wYnIRYixl.SdeTWeDNMpgPcAIME1cGd876ADL6Ac_fncw9Md8A3qN43KX8hS.MYFOsxzcJCgsDbISlAeg766sD.B_5qvZKleAFA1bnUMPGYatuBpoz7CNt2SHp2Y2_ttsWsKfjQmP1A5p6dUwHM_VnPpWlpPVKV7YOGEzdOJCPubxATwKvytML8uSEY1WyDtmvsIa7MckvhSZfWAw64Awd_Ivlc0tBPkEC4R7MMhYQSTgjW07m7RmCCrnyD9W7goyVD1Nsb0pX5pCX4GrKUL200zsJvtout1sonyrt1XiWTLlU1ePb0STFc90Eym6S9N8OBTyVR17WQEHf5U4WceOsO6zFJfzB_6YwJtyx88yGnv6UgymBiVENbN_DBVnAlGZHfYyu2OHDbflNeoGloFZmDP.s_Bs_XCh5AIF1Jd1BeodnKmEl0xOhvDglzinMg09ykXJj04s9IXQEyZbpsT.2Y6.6U.1qmmRIyUKCG2CN7iNZDCbEonney3h.w9lgfo0iQCVvff3MAT66g1pZq7Z2qbXYb2JKdKJbi9R8aX3uZenob615BqqKqsy2Ufl_VgmroyjJ_lA3.OCvt_zFsjudkzoUE.g8Nii4cCuuw8IXfxZWmuiIk1OKaF16UdLyvG3Q5vwWJh_WxSy4QPbc98zsIJ9HUO348048gkhAad.70x6JaO4AtcoSEuKZR3zQ9Z5c7XyTk97lkJCxfWgspvPinsospHlUA9rv8Y7NQ6SKkoxANbdImPNDzORZxAE5yRq5.8hCurHLgg_ojt5iiZhI9WP7q_ZdyZcBpldW8pnV.CT9fyPkHxtRxwwTeiIvA10bgxF3v6UeqQGuuLjLU5URjwIHBKxKfPlqF.FqrUf9qTzQryWXhRJOnF0kNwZuqlaF8cocdRH7zb3wnVLnZ1n_nM5lEypbm2LNJ8PqNkt4.Aw1C_a3jgJ44CROFH.TNesWvF6QaoRuR6Tb6rbwfx.ICNYY.HQjbPYByVATqzckPNSYfbzsXMFUNEGIHOBMjUKosXzsBm9ABa32WjTVCUHjve6Efr3iBc_aKBCbOS1VTOWp.Z38uG0aBxsNO7FBpk_uOc.u4JAsqkzFHuiPnSPwXIzn0FR4wo2JQTOwmNtAH0idmYGBgQq26Fsl0uGcvaUUH0bLt4wuM7hOVwP9yZHHpLFIf4JimhgEDYMo38fl47wVDU.p5EpeuZmJkTV6d7bTcbWLvrAAb77P7CyOUHwxmfx5uckRcczGgLwn7n8.wcZe"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d60fb95f53fe10';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, "\/1166.34332?__cf_chl_rt_tk=aryTf4p49VqTXaMsugXuOthaSaym7W8KcVK3oDPFdh0-1744160362-1.0.1.1-NcWL9LCGVzgHwPrEzqFPLY3PP0uUV2rr4fdAfKph5P4" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>