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: '92ddfb859cb0a5e3',cH: 'lnJzwthxIM7DxDFTdGYgFTGriL88h.HjtRyvK6QA0s0-1744243421-1.2.1.1-7b9F7EPegCsdZldtJoJbZ.L.d9H0SYnI_K21REBOWerIsn5oIvFcUrZbbes_W7cq',cUPMDTk: "\/1466.91332?__cf_chl_tk=Jm_5301mOXgc70iOSW4OVpqsm73uTQqQC8XTNsiyPFs-1744243421-1.0.1.1-atZdniDMKfIMLnfb54H1dj2BhsMcaCcIXNLQaGyJjRw",cFPWv: 'b',cITimeS: '1744243421',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1466.91332?__cf_chl_f_tk=Jm_5301mOXgc70iOSW4OVpqsm73uTQqQC8XTNsiyPFs-1744243421-1.0.1.1-atZdniDMKfIMLnfb54H1dj2BhsMcaCcIXNLQaGyJjRw",md: "kVCHY5HXlzNbx7frwk6GZ6znbgRqTMBxPOPhT_SBCyU-1744243421-1.2.1.1-02b0KNNEObnG9AekNpbK.jMUEECCZJPX1y7zVoreT5HdNmdW5NaqiGOVxKLqM7EgTUifD2wGh4tCConn9LyXeCpLXg.GcPX0PeXgXSvGl8McRfEp_G8cPG03ZfQZX3agUUwxmAEUqtVqL9ji1JV6r64OzWER8dn05kSbsUIe.j_3gWsf1xqGVCcnDBPnsaoX.Y.pTfW5xfYxz4gZQPqSxdETrXLMDLYIhWAQOXSEymMSxWsd7Q0kcWxrpD7KWepq4EHGYcmgRL3n19zj3UWwXv_XebmmHPNqBpJuIKwR0rXCwu0CLyuK30L88En1tp_zGkzNnTn8xMkwJWasiNAte1v3EJKl2z4Wh6Tg9oSxlilA7DALkoq4ld2IwKVgg6E.smaXvQd3ZUtA9huR2RiTO.cRtZY7nzOUur_E5xXjv5rqNDUFHgef4h9p4Je8uiTDoHtEWLvVyDMbEBoTBcFyxitSXxx5sLEa50f9sOXVhucvtN.p4Kmf1HTE9RCtD8AdOiFlV4RBSfUUJg9OsBM_7PppSDCvJPbQNZ0GlTBfiqzlWCLqXL2P9PoqJbwaBB0zwfNCghhU6G6vF1rqPAEI_J_WDw0oyAsp3CGgElYDrFIiwKOU.YYnAshM8FtgZz2P4e9IGseu.h5sHAhr27tkdLRGRxJ9o4JWw2Olf6jPidHlHxmLbX68acFHrmK.zbFxeJuIY9qt3yqbJFgzup9j6O_kAzmzB_s.pZ0cmkDxdKbdvYwGEtBK913x86blWxIeVOF4POtGLoVAseW217FfKI7Khpt.N812o1ua8MF38xYgqzE5BZ7jwyz3sFrfEL9YJ_DuClc3NWyTrJuQ5MdEkWKcclk61ZNFL9XWpYmjFJ51I9c7cHSf0Pt6wHtHVi4nuZ__eDiIEqlovJr5OKl5SYLF976h1YneUdUaD5Kq7oA6cDLPkUa6UM_OvPrEJmLd55YCuHQ8ijqX7A.2wNQyYF9uKFkhb.2BCyeedwF6RChgr_j_kX2HyyzCk_uY349cH.B9zH7mUcl5deokllwHH2qJPjrPEOuQeuRCOMh0POQS4lcTegqBgH4oHJzdRWPM_28owKiMaMA7YpVGdrfka2rvh6_XxWVkz4nD1UrcS_bPKQ6vPeb8E4KGUH6pz1iYvPakuu.YhJFPNXt3Lx8CpaMmMNnqIKgSY6Xcm3ks9UA3KKpqHS8AeAnu3kbHQFqB",mdrd: "oe5z.QDRCMBeavN_x0iDYMmsk68n8UNKpkavAsZ2KK8-1744243421-1.2.1.1-SSmuuj.7sirDzBczQC5k7ujHnI2I1TuhFewNnPsAvev_HoVOhJASjrlvi2oGD3IBUD_owcVPgiB3pHpUb14ITdqQZKontX9zgp7D0qdB4E_qwOEWjlAMI1MVl5LQ_Un8s8KN_Exrwv4ruw0jIvbcYCKJFaCcPq3YTGSF2UOk0xqFvVOk8V_dtOeIlYbC9aK2_I2kHA_p3BONLC2wDVUhQPQSNwmly0hksQuOiZ5Nv_9AwHup9Y.UbeBBQiiScdSfF6gt_NsjKDLIV_K7v.0b2vfKn_aCOkfzZQ1el.5RTd8sN1vjIZQcDZQLIyCb2ga1RK47dfkScwqan9kTqaj3RnmxBdmsK7bD0GioFs9n0TQ4Us3ezAvAYIdOYBItBRS3YIEWj6FPCvEmqf8vA1ZpK9ibSZQ_Y.ZbxzSPdnWlHHEBiU.WuCq_RS0eStdMUlacBtocOu3m50vR9qgr8Pjx2Yt2AkY3EHqZ4IsHzvpxf_GHnZRzm0rNXCrLCgmh2om3NVh8OIvSXmReuUBHRi2PwuJWxjPKBaqwGEr7nmFlnrvlUcRW1V.ouukvM62DufdeatpP2dU9x0Y4i393iYT.quHMP._sWBinf7nmWzVjIxBgaWBvXjN7AxF3MOVzGuGSL_VwQ9G4erxHEyamWSTBrU2sXS5UDr3.NZdVyCC1Bv4ktexV63xH_ijtNQQKtc2qC_qYC7BrKNPorblagHdbli4VzhotkoA0074SIfzkEiy.FOaNNNMQdjuymF2cnGri3BsgdDyxJE.oLPtg0i2sO7gnuMQBsjo7rzUddqvBuDdkHdV2XlAVj.n7fH2tkYnCGPtVpteVSV6IP9xZozoH9JAdywTR2RlzEEFQJQS.lSDa17eOB4od4MNubdT3P.vF6bkCuGj15X4eQhqXr3vCUSKUAZnpnkHiHpK0wSHgCuSO63.bhf4Dhl_dvN1DeDoql8y8IiiuZwyZ8ymaAwrhI3rjYkIvgEh6c1GrHtmqf3UxRFQf1L6A5HQjTU_Ycu_HtVoaFOuVb7WBR5By55b8QGJVXG.vSoz95FqmcAz1B5MN.jzkq4FaPKIbzjPhwEwbsP4FYextEFVTT1Fte0GuojF.c.DlBvMI8HUQAkVHIsgvidHIK.3JxjyVt725mJuqY3e0Q6k_Ut7aja6_EYSvWvUd2HzkHuWoyNxSK_kjXB75EQSAKDN_xim3AeuJ0X3ozEXXyw353JU.ZIMovkwsJEleUMMTn2gZke7hJKA5ePNL9KPX1fUlorNIbVM7tPO2YRw88obo_ddEdbHrC2OG3b0.FasU0tI6hPMT7Mf6AkjdA.l6c_KCnAJWEPaUTpuhbwJYGvGTDIBvEtpp8tRS0BuPSvm4rOtT3qfSF0QNiceh2lVsJz7bQFXyZBiub8BRXG8ZCA6Tb0PYZHi_wOauTA.fPyIYZff2Dx1JhHBvXYTyslDNtG7hxapKLMJhRtPjS1XpsimKQbQ6wq59giwuagozkcueSaFWQbFt82buRKKXbgHOrRXHoBJjSZXodZRZRDqnT5MwnzXCu549nNKPld8Qte0Iuk47pDkYcjgiU_6M3jDZva3prY0XTPUS7Z37BMxzGYj8BC82UGYR1xDJRuoGudTvZ7nhh4UdwxnrVAvWmby_vGsz21qbAXnE7SO23hra6q_fWD5YPSjZ8Cl619uEWdfYYWDbZDUQ5aDcOQIpK69PmQ2prcsWx4_49n1EhRXciL.x2MEb71rGX5OnOdXC1vF9Zoj8sAMre8uTydT_ypCMk3WtUtLlHE7Cd0qVeTxXX03HAkQktZROiO5qp.MWdaKSQSkPq1BwXUx4NrBHVi7NyjCWjl50vzuipTNT0Bxg6M7a0t9GHOsG1LX.JV6dFDwhDt3hT_jzTPJzL4biLyrZ0dT0eayPViCiIrGrlOgyeHAk2SFYc8BEcYLVceMQnb4pG_evup4._dzdt12A.49uvO_ZvjDp5JwyGbHOhl_xvS2WK4mw0bI4z7IXl1qjfV7VVF1zaEfON40GsKAMfmwGfTIgOky8SyYkSX51eIhuF4zSWSz5oWzP_9ZoXQ"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92ddfb859cb0a5e3';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, "\/1466.91332?__cf_chl_rt_tk=Jm_5301mOXgc70iOSW4OVpqsm73uTQqQC8XTNsiyPFs-1744243421-1.0.1.1-atZdniDMKfIMLnfb54H1dj2BhsMcaCcIXNLQaGyJjRw" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>