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: '92df3bc71e769d6f',cH: 'U3cMuviDF.l_HAUQdG0HhY76LCU5fycUX8VhGRlCgAs-1744256538-1.2.1.1-YIybBcZS6aLhJdFAebsokqY7B58meV9cmIPEtuuwQgVFpDAMWlznSu5PN2kLB.Ag',cUPMDTk: "\/serials\/641?__cf_chl_tk=1Fk9dkkg3VxyJN.5Nvguk4Dg32UWsvOE857ti2YQE8o-1744256538-1.0.1.1-xJE_jc8wqU57GIrJV3ijH0_RHFqovB7pAnOZ9I07lxQ",cFPWv: 'b',cITimeS: '1744256538',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/serials\/641?__cf_chl_f_tk=1Fk9dkkg3VxyJN.5Nvguk4Dg32UWsvOE857ti2YQE8o-1744256538-1.0.1.1-xJE_jc8wqU57GIrJV3ijH0_RHFqovB7pAnOZ9I07lxQ",md: "BdDFLXpTe3ZNV5W7jB1bt.NJn61wOZPt_..x3R_NnjU-1744256538-1.2.1.1-ZCYGl9ngaeUBI2her4Df0PbRKoIpFtE1RVxYsIewq0oDb.q2dtkpQ2OTF4ZUBy9Pgcu4Rbdd9GuLuZJlh9cBTXfxKApRUoCPQqdifDv4fR_oQGocXG0a44o2Gq1BWwGOdkiCfkdRJTO.2Wm13Z5K7HeOMmwvasW_SPVyrOQMl6RaYe7JeMsVreY7amEN2VVIC0rNATBqAI2MpElcU71iaMfa1An1xxA4Hd8yL0Jom85YMmhoz4EYbpODXBu26NQCLMuPGEZ96R8e1UEOHr0b_iRaSqA921BRdfiv98.0PhqL1bgvjsiySiYozqrqKKz12TYVulDOdP7PD.FOKIq9Z75Jjm2izSdxOIOj6052KorF.adqQDEPtvU2s_JJB_P7qEiaZAFrOwA_PXeRqf2ZeG.t1BW73HZweQelYQoYZzDtvRI8B4ee6R3iEO8pCsXkHtSL8sX3tc.gfF9oE8JxHskjGq3_3y9HeF6llkKocYgJND3lhaZrxNbfMHpN_LbcSSNJsDM1ZQsPBM3uCVniCPLx2GEoeEkbTdm2mP1rphRud9nx2fO9s2XFSSqbN.Nidp6YuMGLvjUC.RD4owOcxmZQOMLQ1AanCjPWRqP.qrAKm5yAKNY8uRJ4kpPoAI1tjHFiROe9jXyf28keYOpqnfCIUPSbjtVUJ0m_5NqtNCcreV_NAR9p3CdU_TpIA0I26qW9jhY2f.GCpZFQPnq2EtTdB_AxLICkzb74tfaheKesH5QEJ.TppgH20vK854SO6gkGrzMDICAoWVlyiemN2B.QjurcuNKWediENb2POO0GptcFdGn_T2naukjsvi7Y6VsocR.5ISuvi7ZcUmM42W_m3zuhreKTImW.Kg5uaiQfbQdpcIoPvjjv8WPn8bh.O8XOQVxcT7GMwtBnhaul1eBunwebZh4fYnirX85e4YsIRpMeh2NIj4wtnnmHgkvH8pw6gRwEbttkwp9nVfG8uo_LGbMTZZFnAVdJ71s.EYr6C.sy8XPAiHf0RH0PjlthIXPBlkPk6ucMrDv4reAuH8vSg1JexTh4woDKeMKrLJvPfLKGtHVfiwJNBQGpu0u.AglCX642CglhJYDQX4Q4g2pWY7vTyssO2H6dCJFb0nfyepJIPvLXy9UTjp9i0QGa10XEL43oV6lVJy.HZIid8.1U8LfHZTyXM_bC6kOLUOEnBlIhUncQa.mBYK4IDlNY",mdrd: "aytwWjr3XLM8UHApgyiASwWW4OWYiaAyOgkEpQ.NN24-1744256538-1.2.1.1-P_pKqcEEFcVrgjfeAbzVP087A9Ft6rJp_dJH3lIQNeLNNR0JKKqd40iAvaIepLac6mlXmlej_00DAbhK9J5PKZGtSuCmMbDo4Tc3cWihNunE0Kw3dJAHMYbbLIRmr7xZPqpCOaZ4qjdXoxQ7glCFt4_s5BLC._rkB.ii7P8l6cnDlojprTDGuwQvXdGLgE2t4JmLxs06Vex5JQ4OiI9vbLt7CUEeyTAe1fako3jQdTMNGFIvmbaevfp7s_ddB2qqGE1vQPt3.pivFaZ._MjRMGc60kZSndTdFaMR.WLUAXeCIYWeD5gfUskXOilNyR5XB1gTEMgRiFkPTRk8uZPJNHrdGtxQs3sRpNv1w4zgZNiy03UGJnS9EOu4zbz20s2pDxJUd_tMV9xzWAME9KHUDAd6G_tzjMZ0NLdsR0daKYLK_5ktacipvna4oatrOesWAGeiYmwEB0otrLoLodEpwhq.G6Wo4QPm.B69wFAJW.xqEa2KJzYgRanP6vOOK8fDd9zUhkBAxul39dSL3FlCeMKuSFgT03gahmphEud1DooVf5bdmHY5niI7lTt3v4hHnQxAUtgWeEYfeMxLCjMSYFvgNFGWTa0RQeshHtLnRlR4hHI4fnqVBxM4YqTDWGKd7oEJIBUlywnWsLpEjZTnrZBYV1Ng9UFVmoPzRADfTRcyk35oY7eKR0eQhSd.me3u8Uv67VnfsC1cNutiA6B9Kysl67AeY2nNp8NsLDZKwOc3KAevgK3GtUqbvnhW8tjuHe7xdGBcR_akpcIDiHjS8zwMZKZZH4BMIa6nDT6KGd3NL.EJbkv5FsqxOQFMBjjZJtAx3dusLCGPXFA728NeGl2uJuYfcCXdfCxnPjYbLTn_k.mTtLnORi_exFv4rrd9a1xKSw8ue2Yr2sT2X_P4lAHUqSWZ4z6ZQb0qACCRpDED3oGqa9LCE4j2nbzvdQ02OnhK45s_PlcUDVr48j50lokRhNujvu99kS6rbmiFd8N5NSQ4_DDwiT6eWJVc2fbp2jIEm1Ueta18CgpRKO4YiuyDN7fyiV_v6XDyU7qc.qYz12kMpQUUyYV3TYW1JHDWBcxkY8g2V0zR08krGETgyQedVE6ohbsBpZcqsfAZBmbcKjoNeF16vAoMtDqDgdhGGTHJzU56bY8ACFuKtYCUmCfKnmV_UAWFvniRgk12CsuoS1aNgYjTck5xtH3pslPmY77D_2tKou1ydk8a7an7hcHA8z0bz5NNqV4pZX6JkzGpU3HG3JDZNt6uaOcC_sllPcKtNhmUCdvsFwF8.GRPmN4G_2FvZoUNlS73t5auiemaKc5URNu3rurpVV7jSkuOZ8PP3OieywEI3PaP6fAY5Qg.OgVXd1ZOfU9dalRC1s8M7YGhLAJUfKps_BitvvTBk56qMoZgojt46f1cvQYIn9p5FT.sM0XkPQXfomnU7F3Im.4SqqgqTeUHCLPrBnTU7.oevLo2F.2nB6ZhWhI0xw_fYwrhZVHgWCCZZtWvxnc5d7dLUU4WzFOrFp2Z9McdAuwNnUfI9v7GWVXIqkyFwGW0tG6I23ILk38fP3yKFIyo8KDrB_0bVqFofZeDqXlIRXkVJGjjPTh.q.qq3BcMgWTobd6F7NYDckDvIw4e4PNbDYVVfXFwZuTaXemJB8otyq8hpG22MojfTTCva3tyl42GEGs1crYLds_UJRYVu_YhSF7rzocpEDyhdOzSW63tfiaSqwrOLx05Ao2JgVfK9jLB2sh5HvnKfrYWH6OUoPA1iTLCTyRTRCrQgFGKyLjPbKW03ssm.0kNZ8yTwQptSJvdriJQwB7ikYbTCsilfz8jBGsrWA_NMoJNfUohxUKUOn6BZ1CJ1KNYg_HNBNUOEU5_6VKjuCofWMvmkrpd9ohE0iMMnpIxaT1IbIF4oaPx5lcJh.xrpVAmfiCx9ue.cBHve.qhM0Hgo_1pv5VpO5X49BR8T0PuEJ2XpdM3Qq9iOv01l6IVS2PKoBHOZ2rzMbO1EY5pBNPhEP22jOJJcyUzzgkpY1XZ0QVWmCYZxAuY"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92df3bc71e769d6f';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, "\/serials\/641?__cf_chl_rt_tk=1Fk9dkkg3VxyJN.5Nvguk4Dg32UWsvOE857ti2YQE8o-1744256538-1.0.1.1-xJE_jc8wqU57GIrJV3ijH0_RHFqovB7pAnOZ9I07lxQ" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>