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: '92da751d1bca2739',cH: 'xcClWN52TFl.8rZBWeDJ82d9tuJl_W5059iD5ZvodrQ-1744206458-1.2.1.1-OI7rfRw7bQvFdv9QQbcoKxQSau.MA9YwVXFDou42YeAk_9SfIXqpwyiZFceHUnPP',cUPMDTk: "\/?q=rf%3A6244637&__cf_chl_tk=k3pf9QRUg6wzDHs06z298KH2bD0MNmY5ifaspgz2mLE-1744206458-1.0.1.1-fcRH69kxUY6RV5wul3cDha5WOg1bKi7Q_3_Kmu_dr8U",cFPWv: 'g',cITimeS: '1744206458',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/?q=rf%3A6244637&__cf_chl_f_tk=k3pf9QRUg6wzDHs06z298KH2bD0MNmY5ifaspgz2mLE-1744206458-1.0.1.1-fcRH69kxUY6RV5wul3cDha5WOg1bKi7Q_3_Kmu_dr8U",md: "QbguvicWuizzcLaYX1PKDAp.jHPC9FB.c61ZDou3GdI-1744206458-1.2.1.1-ypCzdiPpV10SuH8MaJL..XEz4g7aW6kJZ1S5vyqNwruUFPxn.YcNYkk21_2FThxRiWv5hodGsryxgsTC42xnGynJr54Nd0eB.zP4dmwmuKpogSRFQ86jzLqCXyYkWh6fAcf.vMkTsrBDSE7f.zCyvMme5UOABXign.lB1WenJDKLMq095eDly7SN23meYy6GTgA2N7DmmehS_inwW_4bsJnis5Cy58UY4Xt_isdblOfTNIf5WHv4ZbicsCU5eDkyWYCmR5gOWS92W4jZHTwbRTUkY8xD9GItS1zaeWrmXIGAFo49igD70Saq5B2_WXy94evXtjHOE_uDZbHEXXZhhS_KYgua6pQZnJFHeI5d6VXLFfkTupOPD7GwCFZiknC_QzWB6tZnND04NIYGTho3VoIrkadKcyGpT0lyc5L2kj8lh.lfa8uNRtBwOSAQEIsHc5Xy6Tj1duC4gY.XMooY7A0fKJQTCHXplC.Upyz9L0C.tN_4V08uhtkroJMSYbcyls51GrJtnyT6jM3rph3NxiVX1Wp8eXVA7dIqPQkxM6MWA.hKSlycE1qkPia7fJnwykiF8FP6yQMKBPodDqoqT0ZOolltxVGxJ_8o7mLb4WqWPJQxtFyPsJdNc1VLqcaWdo4cTrnlYitM1Fft7Q9LHBVxDocNYD.w.PTVoUaoh15IsU_9dvKfODo1cc_Q84NdrLOwJeQHIxo0DZobDDDyBFFLblQ9Y5LtXW8yGYI6rTTieDeVbLgCwt7lDdmaL7CLHMdk3MWSRp8TzeTTeWfuWGXK2w3TdUlWaIw46Gtk17s90jiITOoIDiJSI4cZkNjCw3fBBSUbBP0v50_4sRsUL58ebe2ANVqanyzXLkOE1uTmgPMfx1KcfmIEOXyogcpDLEPZOWmFYxFfIx3cQKZsOr3ZOL.JBJzKe9yYMLDAk61R3I6JHaxsODTmeEHea.Fee1OaenQ_JIryLyKUuwwLydf4bfswYZF1MtCRO6v97XoHvs4CfqQbsZ2CYg3cVQjzZ1K8JxHI_3PpOnPNlif0Y1JHvUJTUaTm3yE4p4yIy0xCBCEAMa_NaMKyDUwgt9y1AEIE6j7VYT2WQnxWV2ZWpsKwGiPGrvKDldtY2F4BAAXWJ2sprujzZNF9QOlueDlywZ_WaXZsAq0Nsv5EBJzuKKy_zW_f3gGnqIVIAp6sC1dkR8R5Or066B3DECgX5dUE",mdrd: "MeNRT.2mjfLoN_UNLazWi8HCeaGt3Fy4Q41tTWKvwTA-1744206458-1.2.1.1-qa3wpBxXvPoMTVe6c64kdfv5LewknqB8eN0Da4X4u3OZGagIHU2ZUD.SDprAUVCGNESirygRxA1DTbHhV7thbmWUOSycNIpDk0tMP8GlM.Rrlsg3vAK.N_KGT_E8e7RB3rtr.T.TLrNg5RLJSTD0thPM9TDGeXAK5e6mh39RfvgKDyOi3TdlAKcGLnn1gXBUOU3DzJEj88xLXhhhGvOS9lsubi5obGU2cJCSdxXnm5B8A2ILpn6hpKh_3Rt31jFukbDWDsLYc_KO5AXhBHmnmJbOP7ruQ9rpk2jzyrpLGizS8MTwyn7O6NGIan76n40nrAnVw1InjL6oCVV2J5akhR7rCBFiYZOBwtKwVmVGJCyPiKZMvH6qAfmjde1I9RU1VvSkFgAYb4K9342okSnoCSl2U68MFx7mKT4RpkDyvmm1blSHWNFuVFn8WXgq0IJ3DC3BUadXjZTwCD57DNtN74ifyzf3cWEZXmX4Xs.pQ2NxOe3KbNitxAKvUPwo_arTDFOq11J8rttzjYruxCHOOqgJEvBHxtaxyKR2UZRFZHLtcDC5PeaI8MWaOR9sPxVhZ.1xnR565JNK9zpKbO4HvtgC38QMhryw0ysZsAzt11RXLmPhWMAlJtERQmOU_JUOzui1dVLZo240xG.YNJwCX2TZVklAuO4v85KqvIZf1QrkPk1UXzPBiSWF4bz4MNMsmdS6j_hQ.sQxzZgy_CuCoEI3HKwqPIA8tGWUF2CiXnLJumNtFBNtnkOQrq2N.vHn1JTusJzXiW.hCV6BjWU2W2vv4RgiD82vKoHrc167RuTBIPO1JmGhpFVrAkP2KvTJKAgjNpjgN_DrkKRA1N3FElUFfzOnU8imEm0RD5C3wXVweP9hTKe_3QsdVd8jCnRswS7054Ex6g1viahzf3MhkZc4GNG2tUUzl13DoWBpIkwsJJ7GooH_XoiSUWilXBTvL3UO3q9M5bwmPAoxedC7kdjqRYD.C1ZhQgGLMAeqjSgMvPDwzt4olPwPsiUrIMdwynnchbdbuYxlGM0EkA9kYIAFVaP9lN2nrEyNHsatt_WXb2OEoxZ79OvviZr15rRyIxIpV2NlZ8Pf_Alcl8PXjWUvQWn0uQ7k3ZFMHkDagNmoVVk.nG.fq2PXqjPPzLtOKOu7A3owzwrsyWIz_kIzdmJ6yOyKjLMQtDMsqII2q1isAmZMadG5knwk.DszKn95e3bcvqHmZIVTJKRpiw.SQAFDBny1KsA4.PDnhawYD2uig8JqzKXq56_3oAdIoqRp4U6CrECpTJYtCquz5Z7NRFJoC9CY8_79e9540zOKjcuie0VbcBKUXLID0FaRpN46Mn4GuDrzDxZqAD1D9_uGOfnsiu9oxAsaymECdFMKr5qDQfiHiBssnIUZBBRAJjvO2eRsxUZOYWYjVeLP17w1OFRDCnTwFiykMNjYAbSJ7fgsOlt0gbApfq7Xu1CGzA2HxTqwR6VBgGJnJLkJ_u.6X8fY5CXr0z5xALKYDaWoHoI1S7f8tPvILs2DSnOGuJnLZ31XAgx9EGpr2Ew6X1amuogYidprzv9OVjJ2zG6FFyZZOGhFGZTauI8zQBh50KzI9sQdARVTqbAXWkzXPgGF8u7dtCMHBHRFkzmsNoLWMCpdCdXvAvWCMSg71iruGY0WKYpj7aE.3gRFVjK17SmId6q4hrX34XOfMilmkhgr..zJlDPBSX38izVyVOYZHxC3z.n.C.wXwZSbQczblsrCDk4qDBlf0UEbvWn6vASVRn6T_CjdxyGvCOyHqyWMoXVLueOB9qYMEoNvTzHF5BK67thKv7zWZxuJsIzWOnKXFq.RP9RiWyi1eT3DYP.scisHJp8yZcCJQO8dChvnTOZdAICGFP5jjgkrAZEKZxMjDADHh5YwYCRja9td64LVFI3162so4meK_rgNLqW08dB47qtxcuEhendKdkz_.XLmhCRd5WvF6cll5sP2IcxH5B9DIvxhPQz1pyroWrd..YgkehMIBfc1OjRqfZnS3xYINuzvm03nKvAaecoCmg_iFjygpLHLPpYpxOkrwo0njvHgWA"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92da751d1bca2739';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%3A6244637&__cf_chl_rt_tk=k3pf9QRUg6wzDHs06z298KH2bD0MNmY5ifaspgz2mLE-1744206458-1.0.1.1-fcRH69kxUY6RV5wul3cDha5WOg1bKi7Q_3_Kmu_dr8U" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>