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: '92e240198f5e40c5',cH: 'X.QbHXxifM_kd4D_cGpZ4aE_x1ICywK6FsLrXEN0q4I-1744288173-1.2.1.1-ZIV94fhob2aD1SXQQF5q9FTVVJjXsaqvDvM5U6A_wxk2bGiQrFDtxRwLYY.kYdi3',cUPMDTk: "\/1166.47007?__cf_chl_tk=hn3p_XCAWJECfsLC.T_Ar.ky47.gjrl1Jynt7YQ_dyE-1744288173-1.0.1.1-Xrv6V80ah4e6G6Enc9LOfaTJua7nkDxGy1hxtA2zgOA",cFPWv: 'b',cITimeS: '1744288173',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1166.47007?__cf_chl_f_tk=hn3p_XCAWJECfsLC.T_Ar.ky47.gjrl1Jynt7YQ_dyE-1744288173-1.0.1.1-Xrv6V80ah4e6G6Enc9LOfaTJua7nkDxGy1hxtA2zgOA",md: "z399YyEZNuC6WrilpQeewOxoc9B8fdoBcipaylSrqT8-1744288173-1.2.1.1-hcvhty5qCx6BE49aua2Kbvci.mcXhKcGJD7eq4VfikbCNkgQc6S25.Zo.ZNdbue_WyIWkncdrzTgTxHLG.NX9sJX5hBZqZ8ojcnOp7ysFGaGOjikxl3.y3dF4Tpc51m5t9kUJFFnDeab_5jkE7x7GsSw.Y.8cyVEQY4wOW87dy9FCGJpPnvUaePJ1huZR1lh.yhR7kH5piXcv5U6Qdjxs0Uo5XdhcU7JAuRAGCjEdgrnUBkYkCssvjHFE34FCdfvwlZlrf7puAVmyexCmELUGCJJ5ILz2erAvg7QM.GAfK6zFTIPKzyg6rF93mq3R.BHDYsVHXOwIHDbo.8fZcMpUjKpN_ErPkObLNtrpmjJ3XV85bBlQRlb.gSUM7NKRo_bcLJhIpg44aI_PvJH9n0FTdJj9ytpcXgUjLwNdnYxZrwkDwb4BlxAeg4kCFVvmuwC7OPOnBiYyWzFzouTEg3WlIAX_Nvo8Tz2RdlEuk7AMMmth.rW_vhrWlg_OgLN7_c1bjhl4bZJyJvPKvb4i_RG4_jfab02kKDIKoXltO25T5Q1YiqnrkmKbYreRrqzTDUK43Q9uHsxBsN333iKUNJIvlZLQqx0PAWXithvM5iGXrk7BjqiHlGE0HUs1HjW6Pv.Ja5CeGQXChS8DWk04ATHxcHPTxxJHNH7VH1CsU_zpVdXpB.fYl7KFllVJpk3RusN9tzN7VqiUld2yMlDlxO4hHGk4BpriKDqR.FZkTQfGAhB8Cv53LfjkCqte12tod9JODVWQVG_RNtWvvKY3wdRxs1NcXK4B9qBDk9MZ4VBndceSS.EerbuqPueT4w3LhFB1uSEThBiI.DDUFgOwAdVHR1HUeYwm2DCg70mc3wnpmD091w_zphOwsm6ginkjQSNgcQ.HXcBupP06f38a3b_NrLLwQ8_iQkbf_4XlIKeSUiVXbVT9s75qY9OJCXAe8Vss75W1wxfUiH4_M2ghdfRQBC1AMEBLq5eYez6wxhu_ckjg1kWTUl39y.xv0PJ7ybLUJp9LA9IxGRAyhp5yCVDROVSJ.Nw.v60BY1mZkefSGTW04ok2nJ4G4kKQldpffTQ1hBouZWKxhhwZXusoqGZTePhUSp6b1Ny9bZPvdU8ZraDHUbSVKv7ZPbUWHMQVYy762_mA4RSij_q1OAenB2oP6jPeWaWva9MYdNptSEToJY.QV65.j.23kN9DM4Yl4Zt",mdrd: "LuFRJ1pNB5PGNJh9rXGcyGyzFg.1XkfwNF2Vtc0iUW8-1744288173-1.2.1.1-iynv.fJ_OMvkgaZzHk3ckI0dgQhKyesryuTFcc4UkpUxz.4R5HsjdrinssrVOIfLIPsj3xC9n5eOPfBmkYeDKKzZEOLBowNmSckl5xaYnCcbWy.nceByRP2WXwDP_hRVMzkenqxUZdXETEB0zXQ3RO78v6rWJxxjrvnsygzAiSkKZgxWQ4AZLkFmnr7TAGinq3VyrB.9ARMyaMSyi9TAGiX5HIHgp5qpT5WEDejYR4QsR309C1usi9bOy3tDIXLEAwXOYNIUN3scBxScznPVBB2AfliV7fbQ4CKpZuuFsmMU9_PkdCcESf9jPOIBUFIZCv2xtkkO7YpY5ay0E0RrEnADl53c5ZikdjlIj2ilmAzujPLMkE_WZ_LG7uzgQieCyHb_16z59Qof_mmpz.Kg830D60DkjI.muf2hOOOs8irkWZJ9xWXvtM7o97f_G6S_THiSc.kbNu7Hpwft3qdb47RJ6uXdE0GZtaIUTSmK7HNb5vbxOqZgpyOiTVmK51xn3x1DQUY1KXd_fCS2.L2Ghcca4nfLcgaHdY8AiVDPm9DVa7cctiiG2mkY7Ntg7GPenQsuvOj0D4iDH853aeQQIc6_WXBLV0sn4MtRtPkRm9y.i_79cYP5sk6GaQ4xBmN1aZI3ok5if3_NiExWmcnEVmbzfM0Jz7LFvNUcwi4ZeBq7tXoCHZt7.Y8ecTEABrhTctB2NQY8eFOsjf2Xzg8ReXVGpU7bscDW5SaVT1KAa1ZIn.wDu90ntOm5EWMgKn1R12GWvDaGV1WR2y7ty0eGoYIcQUGGIILOkXFe8CfWYSytabLoj_llps.El6.Ka_H88jAo1ZmwCgkOPtx3lng4WJeUiYDk9Z7o9R07oSIyb6tk0CkAMuJmQoK7lYb1B18O5p8UPCoZXdA.IggBZp3kbRGgm0U.bea7RIfhIZCvaAdsmsWaQclQbxqCtWu.YWJLlFdMM5XwQFb_Ho8GtE5SZIOz.DMM7xcBfOThqtAEM2blYOyEEcYdujeH5CyhlHTY07N7l1EvvzLQQmQ4e3DUPDHtIb0V7KwKyHZ2IdweLRomCDg0QiKDGTPX32G.EdHC8qOZ97unCLow8rPjsbcFpVjiS1Wsj_cvSBmD7AWg4EwwyHx_T8DElmFN_CP2MJOym6ixOjSCiwHqqAf0eKWS73FVdOwoRRfJlG0Dh5MtKIH2_exSUE40SMtwRYoRwx5_RDOL5CbEesl_8gRRb3vMLSUZ76crDq7DecjVy8wFJ.4IXp3J8x7zn15l1DlsCAzRfJX2RbTuTTGL20BMT0OaFUJ1ZUACWFTPnTZB1P4Mlois3m9QClg_0KLEnOP1umZUfqo1ASxmz6uqMY4kiRdXPMa..MOVsKemtaBNdPN07DlYEh5hTMb_225AIG9VDkO5Z9KdkkTJnS6EmUqDc.2alEXelBJH34oVV6E7FwLwQ_ijTzxhWeV.9j8K5FNmkXPpCeDXPLbwLkzzdUH0UotEQfVioRxZKkS.DRjUJrKVLJFY_V9UUapgHvED5PZ0EX2gFXFNeEgsItjUZf5SeruPT2d47dFUZt0gpG_QXl4q6htsDrtoTXM.tR3L3j0AZHGVVdgIV85yzwL9Yxc2f.0TIU7zP_ZdYckPryhfreOF9D3t2JIxPOwW1NDxbcF9ETVj1xdwA7E5pjBIWVeJuCfT9fF5dmTzyjSD8akg4NzeIUn6gR.qnl3KIuWnyk01SPlIRuawO8ijmnHKf_mJjWhVlP_eIdTFuvNwK6VDVbIAivt1uaCzxhb4SJZLxL19ls.1XtXt3mEmHHSI8y.JLPPcLIrCXJu65bPCMCwHPHIii.EczOnPT0bQo.kZD6XjPzewhng47ahz2h4pUfw.IjbIL0T_Gq6HDlR_ktm1t0.nPjJOkCQONOPP98s7GkbL0addMS.cOKWQj5oK4WMzH9Rj1PRWpnqf3Fcgf4lzFSYigJ1RipCmKn.Rd6y2rSWSWqwQ6iXg6.XEKuSNus8ZEUsqRgCZkzjiSBMZNWuz.6.8eq_oOl15jVunpYvoy1edJRNM"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92e240198f5e40c5';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, "\/1166.47007?__cf_chl_rt_tk=hn3p_XCAWJECfsLC.T_Ar.ky47.gjrl1Jynt7YQ_dyE-1744288173-1.0.1.1-Xrv6V80ah4e6G6Enc9LOfaTJua7nkDxGy1hxtA2zgOA" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>