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: '92ebcd832aed600d',cH: 'Q8JY7JzjOGoyTHNEvf8GE6Lk6PINc4C1W76ITA20_a4-1744388337-1.2.1.1-P14XaAbQKx3UZlgkTJKwAcL8bJpWH5tEnRJuGmgMYQVg2H7NxAuoWrcMg6XftLj3',cUPMDTk: "\/?q=rf%3A6895859&__cf_chl_tk=iPAnsRLJhI2hojxFu5LwzxKyCyIVeVomkC9TCxGPwdM-1744388337-1.0.1.1-cV.T.Sy4HL74LVMqV3u329_qjxmo9_hThz2TswsR4f0",cFPWv: 'b',cITimeS: '1744388337',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/?q=rf%3A6895859&__cf_chl_f_tk=iPAnsRLJhI2hojxFu5LwzxKyCyIVeVomkC9TCxGPwdM-1744388337-1.0.1.1-cV.T.Sy4HL74LVMqV3u329_qjxmo9_hThz2TswsR4f0",md: "iBL.xeTb96YjsH09dmNq_.mwNbsg6gTiuZ599bTsNBI-1744388337-1.2.1.1-.zehDH5C1TqushHKD5MewfAU7Qfcd4PSNCZjDjGN7FiIE8QiStHI6CpQ5N_rHsBIUfzsJpgmxiGgXj_3H2nnVisNd2_8BAdeF84qxmEckcqCzOIHzaAiNqXmGh02LNuovvWuzYDT59s.rYKzeFRy.hJYZW6hkJ_ZOWpFcMukq5J7J5fOO_4yLlrtEzk8HyDxsKhT_x6Bq0B2gPN_TwQfxJKyrKdtLHaRW90zjWeoo_1Qj4MYdPbnfrqty7ZbN4Id06ThNOpkejGbi45qpfHTZ8SnQ7WbCO6rHVbYc820su_Fk9PexdgLQ53Ug1xQs52YCkby4lxIyt68eKcHC2Q_wbMU18UiTxjOllZwJbuCI1kQv.l.9qweaPbE5wlrDmiU8S1EZ9yYYthX1b7gJFNNWtf1IVkm4ikCthu0pPRd7kWQQAFJHEoDvWBSpYBgT7xcReZnsG5Omt1W95ExelRSVv4k7YcUuQMssW1Bp7XYqnP69iugQwXrR64NuKRi3yd__49lL4L9WYy6KDhy9jkgbGQknRjQeYc42pIBrwEcONaU_zHiAGvAX15dUgcLWf.bG5XfyMJtnqhgT_agS1UHRo0skAfQVMlFUW92THHaL9raHXEHT_ngWy_5zDhcxNmcJvrZ2n6gCf7qS3f0riFdQ_qWuA4nXIB.T2GdB5Jc3ooMpeYd.Pe3p3yRrAu027avxOS0DIt3lAefcH2x1CKEZ8JHFEU2wQHeCHdfVctrOglrbF3AKJbdh02YnoliFiX3cUVJuoSe_sY3z1_NcVxX4CKSTxDALTz9iL7eFEGAg_Yvuwrbw4.4Egdj1CyQvyCL0OFIW_dlUSiHep85nucD9ot4G16CeQF4aZ8TCjmRfLornHGc2RXMEd.GT._RAnKZ3HzINRnrEz8LaZevvacXcf2FTMax1yGkTkbsQaZZsFvKB1pRxZDjM_Q4rbvkhGbZAuJIk.9Oa64_RdnLt4sPQOkyXO1Ru01bs2.oyqjeBSHmZvG9NxBLNKZkmgF2R2WFsqzqofQc_jsEgEKoV1jRH_R4ZUX6c8T5ViWlB4KvlHZbudIDEXDNaPGHJAF73UVRX.gesTw4Am6nbM7ABwc5jWuQa6I0afNjaTL2EcZ6qJQiarT0mWNdzYIM8lU.XTZq._ytJENNiBm1eN5ENzGY6TyJjn.YpGH9zfk.koH3qsWHVeejRkzI2nAcWh90lE7m",mdrd: "CbrobUTUcOzZ1gR9tu2_pJ23eJzi6zLdHaBQVNlUkK4-1744388337-1.2.1.1-rYofTUJmCXpy9NFIBBQyHr_1TwAnXCGjkmIG.ei2ydIUErasJ0B0ReQg6CWct7a5piJtQ9KWCx1dh.aH9pvnbeMyOtlvtBVj.cXIKtDkY8nC5jy5sbhvy4.m3.jDWOSTWlGi_5LzTuhgrt7VCOBtqqJk7.i.p8X8MUzpR7UDIBzJFOn0iYwxG0BXhZlqA2hvGWENJe3O3HEsjvmY3SoK0iAS10.zGVKhtgPtCbfdUgretnGES.b_7qsVwGvK_Uwbf_tZ2kq5aKrdr0bzgQNTkzh_66cgM3Wi6p8fNcjDRJgtsv3XBsMLasq2.sUJc5OtfFHN0Q0w8yvU.ZRIKTRZIV4GBwRBQn1TbtTP_VOoEsAn8aJvlOMul2kiwDVzP_5EZ1P4gOly93bHU8214K8ApW08ZgY15O5duWPWvVfwT2xm1Fke62xaCRVLi.i9wzBEkLc0AyTLW0mI0AL9Rqf9PS5on7lvS84Q05zvncP8lO4jO.BRNcr_C2N1eFWJgIDGdrkMQUYQKFtCDN0BdpFWHlBCNMs8nd.L_OJA81lAycXHnVCAotNoIa0UlGxcpA_zVNIWwjaJO0xW6.Ffr10BOiJCNR8F_.au2zClMy_t0L9vPXuVblXufBLlgOn7s3vpux0U5CFwfjim9VDoI_NJ1MEnzDpHJg_DaDiBk8xy6xbaaev2.afnEyAlmZUlSKO.yo3BWg8pw5o0UBO.olse6e9_7tPRn_81la7ZGKYtE7yP.CbkYHEyZOb51G7oDmMOPIy5Aw1ftJ0P.gtnFT1LopDUD8PWDn6QYSXzve25F6r_Auaqn3B47Ud5F2_c.znZyn38k9SFifbyLF4EmC33wfQVDElx3Hh5IACJezoYpNxyFRZg82SP.np3lsTbsmyThJfBlztMDIheJk2ifasR2OjtOvsHfVauHUQboxotQ5NdCeBDUNEzykfhCssQ9pHtBkh_RvlZa9wzcHdcNFBOcGMAJxx7nONapr_7hAVLhKHdXmJgbyjQG1d.__RxmbNTZBX8EmEzeNm5LwOmefygPQc9jPz2Cc1RAuEkKJTndIukYhgXpcCnS5A0zkT3_0e5FHE2BtkKFrXj69KrNjP8IaVFIFhSk.b0pyKKHiKMIMlBQxHcn2EBbJiYLKNkVyQjRz2XiXRBH9z88idr7lZbFXeq50qYH8xlLiPQwKhTLwXwkdzYEaDPjKmLNhLLLVCob1K7VN0oVIjjnk5S3QW4vibl9HuTurqH.AM0A8f6vS9tVcnu6GEXS3BaHk762AcWhmlHCAGrx6LvpqndZyG83WhUZzgX5ljlt6qReGO15gg6TL2zqpeRWtt1l4UoZZnIramvN2fDY1k2r2GmaoXZ3SN3hKadYbXqWxIVzXq.2cl3IIMnt4C585hpfYNToe6nk7Bf6_7KVcV.9BeByjQNsu9SFydeFWbF1Obfmw8hca_FM8GAMZZplwaRYHUqIgbsq_fB_H.JsQ6_6iQEHbcMffzc6NvaHNPblVnjT.GlNE3cWoGqoWdzZZvLwdV8RSrKb0hK8q9zdvzTcuqy66_z8_TfabPGeRnhrydQHGiU67_LfIVoGzoR6FXxgUaHMlunajl6ZzBgxjutYHbepdW6Ci9jxqSw4RfjpR20NVPWQO1X_nz1knYkQ5bxGHqi5TlYXY08wai2_4mksV_0RtHH66NNH8Vk9zwsOEeexSoAD.hMGnvGCgTXpy6u6mT9eu2gu8vQn6G1_QhP7gcyiNm0NHIrnKcwqPmHY0gYDWCfUUU6ViaiOoyHNs_jy8h.dqcQ9myue8SJDnRfWSb8O8YpJ_f.KTyelrg.PHTtYlOEJH.Or3bBnWfbxxkVBdgR0pFQfVkknh4J0pmoQmsLvopQP2p6sUWvCBtt46.NdZ4MJzstn0jwPG9tMlBe7F_WlW.6xZU7ExrcKC2Dssw0oTlFcNwd9aIHdTTn3EM2fLIrL0qVoTwpR7GVYn7JdoS9cWBvhO2I0OH74K.5dY_2S.8ozXVJOXu6gdYhEZmdO.m6Ck8"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92ebcd832aed600d';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, "\/?q=rf%3A6895859&__cf_chl_rt_tk=iPAnsRLJhI2hojxFu5LwzxKyCyIVeVomkC9TCxGPwdM-1744388337-1.0.1.1-cV.T.Sy4HL74LVMqV3u329_qjxmo9_hThz2TswsR4f0" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>