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: '92e712dd2d51fd13',cH: 'N3qMUS6UGGDp3g_Zzx.3LdIlObVW8cNaCioZxDf25So-1744338748-1.2.1.1-kloMDPiBIvDdx7vq7xAYEiqEhXRd1tSKOipdeyKRIOBNNCqIJ9tkzooOnIk6uMsv',cUPMDTk: "\/0696.90048?__cf_chl_tk=n8f0EGJ2ZtutsOJnFHdaYrYp_U_5dEQWTe3Ef_wb45k-1744338748-1.0.1.1-o3Uf515Q4y.ByROSZZGthWbLD8AMEuPwLCdKzPVpzKw",cFPWv: 'b',cITimeS: '1744338748',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/0696.90048?__cf_chl_f_tk=n8f0EGJ2ZtutsOJnFHdaYrYp_U_5dEQWTe3Ef_wb45k-1744338748-1.0.1.1-o3Uf515Q4y.ByROSZZGthWbLD8AMEuPwLCdKzPVpzKw",md: "WUrOmTvMGOklnj1h7k1MTd3s_Osm2SBK9EknalvfulM-1744338748-1.2.1.1-FFHjjEly9HpNUnQ6t9thZYzyfcT.f39WrOjOvzixBMBaw8Bu8frzU3MTHqub3iz.rnLMbfKKx3o7QSe997fqTOUwW26CUJqQ4QdUAiwC3ZfsU1BkJKmda40dFdCylZF2jo9Q30LzsSnTD6qNzWB9VatUBD3fwKtkWRb6Modyr0m3BFnRj2KQ_BtCW0xrMHbxxxbGGBaq9bk6WPfVruOikbHZHLGClxUov5d4RxmhCfvbT_YWBSA6gaGuixcTlhicrg6mW5Seb_unl_sCoyeywBZGuu_lMHYnXB_J6l6YqH._ih67SXhbXGyez5F4nhMSY39Fi6CPZ3GsS8uX3sF1BFszgyDr6fJeMn6yvwQ_s4mTpnFGO6DD7i1Q7QM032FKuJBtJK1UGhr5.IdIrtQmTX0FYwXPKssG6vrzQzTFoX7.1nIw4VovQMJk.fJgwQ9z3wgK0SxZTg.fbgt2GeL1RVO_iXCpJY3_CC6KMokjlkFr_3T6vjMNV2VSxe9y4wAV_joSbmLJCjuqueschmTL9k66W_0makxYiO4Dy4pYbx18X1hsMJBQHTumo8kM5jYhBIWTO886ebR73ks1FkyEwgDRolFwU5Eg2N0nchV9eFKCa4VrPSyatxjopCmg8nKdfl8LPNxsuVpRvmS.Y32aLlYy58CAjx15sGPaqAE2hcaowgWvF2DT60534Joz8TZ5KWwwCD1b7Xxrlz7Wi4av6sBGT8fq70eRWMiR2Orlh.bKVRf3R05i32lu72m3GyF7j9Iv3VvUyroHaZaiQuhcGM187E4eXiBz_1l2jE4_emDxRLxEB2O4QuqAGmZpdUSgwKzJmQB0xJkQS8QyL.5K9zVP1tYD6PkhvAtNS2Kb4N7IEGVf1OJ_qi6v7EveQaUxFBhAGtjXEYjwn_se3XGWdUfgppubwVvOI8aMJOn3isw3_.cdcn3_GgdsrJPnivPgTGH1ORt3bK7WJJd4P7zYaeic1QS2tG305MWo7TzxPmHy2wH5KpU1dxu9Z7iM6WM9tWlF.RP4dKvHAkJPGsGPeITh.XOxc7Cs0GnDgKPjVk4GKKU4DNljQkqomUIkP3fltwsiuqdRgFexID5h8Qp1rbKxotE5vyHMXGrABiDASdSqEW.XuNsqHLx4M80a3os2VQO_TdfE3OPBT7dFDQM61H4rKlnxbc0dpOwwegxrsRqN.qwcLtSXiIIvMzPtbEVY",mdrd: "DXa3nA451yBWdHM6mNlA5aVJt9rGV5YyO6XpQ02tl7k-1744338748-1.2.1.1-wkavBV8Z4YPWRUDZRda1uOKZSJkC4pHMZs4cc_tXSHW0z52MwXq7DU9wf0NrIpqohFIUiT0ckKJiBcAqW7ixwGx5C66sl4_a50CkxOT1sokELnhFhzVyoZpMlk58Bt8BWMIyrSIFVOwtN5n0vYYku4u2izmhFgfBxLz9JR.eVR4YTBeUC7SEhfLJDd90Ke30oReD8w.ICUptgvmUJVPklA77i836pnmK3.vkXJb7e2N73ZWPrWQLZPHACYjosrfXcLX4Yadfv7xxCLxlpDSD8URN_tI4om5VybCLugy0B_g4RpyPP.poFCNw8Pofz5u0UeYE_AqVLaHILKwxkk1VGPsa5Gd9Dz4NwsMMo3ESWgdwMnOpzzkL4pfFMnsvzLo6vldq452NhF79JrbLnTjCrUsfoaJFV0GVoa1_vEQO7Za0TTpY.aN0R_G4hkWnkMHcX0oQH3NaTD50RVd5EYosdrpnAxupUMuRz3lFqjIxb3wgwn1ifEBmYcZ7q6U8WG4crYiRHefdZLpu5D.ggqR3DpQChrsg7r3.DfEEABwxFfPJQqoDL8Rjslh4rh_jOUWTnm04a6zav.oDSsg3uznz_jTLUCB7vXLp1xoAR3IcALkxhno20h2h6miRnj0Js1iUGM8VoB.KkKPSW1GuqfUWI33guWYZvwgzXFk76sDE6cN6F3xjluyh0wNyPYPE5eaY5c6jOrAFUtQXc.2KEEgimFSY1x2z7vAe.vONQ.r7CrCcDFXiavPq1DyJYxfpbDEm1NLHYHtSzo0Bjwcp1mG6XUogclC1I4P3e3hFYz3HxiPrTFUF5lpc9AFr1cZrdBRgp.0lWxLdbmLTnibW1.Ch5331FbMXXMpjAIttheixBd4OZPRkUpdMXZ628XnnMbMmHsuc6TRQtx2VX3tbBhU0IKANXiRNbjV5imPGsBnEHB_iUFELR_rcIzpKyx5qqasOWoqDVIaR9BEyIhYwuhH0aJuqUYhaRTtVvRDu1M5cnFTnERUAa_fiu7m1_P87OLooY2pTeZUKtwaOHggoCwY_nq0BmNBaOiIjY.S3PD3pu8WzTGvcSXi.aL5kV_3kWHFJlHtMnEaFfdtLh7z.FFIi9kUU2GdkI8ND7soraRevP.xzx30QcIqLy.ie.0ObWNP0mni7.TK891QqdEyvBsE5OGFx3L3Bffauqp7y2bNuYQSmeDTgY6A1mQ_dsp.VUvgbcyFPgHktFRl4pWhqf8jBIVn39SdrIcmBME0LyiHC8ngUAAnDst3IS8LZ60xbl7FIEs8UNDjDmAueQSuell9vqp1Sx9P9Wp1F4lWzHqikyyRxkRJhVi9dZEwpWgAeplt4gn9hJf2wRv1.MR85Q5WC9GqKSnVRt17z0qobYqKaodQ6fz1VKZ3rR59AUZ9O00k9kjtaBUtNlxTXqv0QoX5fOtJGRNlieIWhu3jfJ0H0QNhvItXLU2pJUW72vQ1Ar0CMbOs65qDvL3fKMoeVx3tTj.wLvIoBM3KTfNix30e6BFq9TCWJggUyQTmOSh9Cwoul34OMibwxUJNO3v1TcCE61YIHKqsGMrCfMEvzRrbfYyq99BiDmi6JYheWk2LU0s2eMjvyjiW6kaymJVxXJ6n.rHwqno0Na_hNe0CDDE0WasmqzusxEW29YZiQlZgEompV0IdcbcQsP09iI3JBKP9hqmbnGGa7OYZcWQSfwj72BU5b5rGSVolliNHRXlvttoQmFAWh_vgz8irinM7qJB4MoLdm4REOU2Q0k2vWnfJWlK.DeV2Kqf_ovh960XxoTI3Q_4l52ejk2BSHZnUavttFesSVuMq5kU4Gv8_sYZw_2WdSN5o7dfk7RRcqx.hGZ9b7DwQaLyX.ziwO1kLVzyAqB4wYIr0xyKKN.F4zsN9zNA7wAiib_HiXWi1ezt1wnWRHdBp1.0WJcp1DvCWjXCbxuGJI3Nb.oRd8cFgVdyWleORcd8h0dKKNpgBvUY5kZKc0MH5I9XTfqlyhxul0q0LJ9cEUHasiKACoMw_avcqc7eBmlo6a34kNjZDvGr81MgkF"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92e712dd2d51fd13';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, "\/0696.90048?__cf_chl_rt_tk=n8f0EGJ2ZtutsOJnFHdaYrYp_U_5dEQWTe3Ef_wb45k-1744338748-1.0.1.1-o3Uf515Q4y.ByROSZZGthWbLD8AMEuPwLCdKzPVpzKw" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>