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: '92d6e38d4c87a8f2',cH: 'IY193TfcHjAAiZfWxfTUP6Mrisw7ud3cbsW1SKh2BA0-1744169038-1.2.1.1-4GZzmzFMMoyoA0w3i.q4n7OLITPfAyjCfJhjNe6TrGw21AtPkRJ.9vF6S4u3f43f',cUPMDTk: "\/1448.68431?__cf_chl_tk=LIEujtTQ9F69_pbrc3Xm4MzD3NwJxA0CtnON3N8zhWY-1744169038-1.0.1.1-dV5EulMYwFYwvepqbX4a9P7IDtHHp0OmXvvBi2fYMts",cFPWv: 'g',cITimeS: '1744169038',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1448.68431?__cf_chl_f_tk=LIEujtTQ9F69_pbrc3Xm4MzD3NwJxA0CtnON3N8zhWY-1744169038-1.0.1.1-dV5EulMYwFYwvepqbX4a9P7IDtHHp0OmXvvBi2fYMts",md: "hXfHeA7sB3Di8.y5N5kYH.mVtcxG1_ntw_7D246nN48-1744169038-1.2.1.1-14ZjOReFfL6Sxr6k.ua1cavWno2SLZetDHgsB4CcjP4gBNdq.TkNnhZNeaHy5lxzm.MI76y77yoot1aT5WJ81mX1wdJ8eW71ugOF8sNzvyncdC1Mgj6jNRqIW33ZNGxNsI.8ezhpcJ7L0cflSkMkC1XWCdNu_tHMgpKAFrlSSQQqnXg4CNMg5QUi6Kp9bBuu4VEyA9bfpD4pEzjc52mfKv1oN1JG.z3VQOlm1W14e5kGKvEAmttwcyQKOx08mCreT10A4aaIPP8k6DQBUFBV1GJK2RA.tKDZ.a6FeNqNo67RdOFPrksTAD1VSBq1DiCoxCOQPzt5C0jBBbqMe98bcnnEAUk6T29J3uGBnxhStAazjGCf.tVcVzodrVrxZyRu8FTI3xyQzUxpFOfRtsF_EKD2SbkGvWCPqdc1.1lqWQX01RTTH6tyuPBvs9My7Bn4iozirToVf4QW7mu958AhzExElSuNcRoR5sI7Zku6U_VL0YEpb0cTZ.ikYGxs0EO3_VC0yesVeKua54OGqYrqI1ZdAqUSzv9kWV9VelSiFFUXD.JbeJtve.5XDqfOZQJ6mNcufiiSvdvnVQT.TkTRoJ60P8gOAPwJiuKPIntyufDEoRdgk8x_m363jdtv7.l7PP6rdHb2Yife48Su.4eIgvnGaU6NTPUOjpLNzGwrFXpK8PS3AxZG85MFgDTAkYu2slfPHCKZ24xJvuCOiAAyQlTULYxXAj_RDNAE8o2gVHDR6mcmt_vSMxX_GDzOGNCXlZd9ipY1HANfoMhuKsT27jLelQw4QgBHtCC6BuJNfaNu7RwZodMqJmtkb6rL7kDa8Z4R1tSgBiXhm_3Ggix6Jd2koSEnoKQ3i7BhzWniRudNe67kiJWXn3RUiX1a_OdEuPYsh4RVaFR5GDsmFGuWVPodCKDDTkmgEx1Qddffk6Lu7pp1gc5RGVVDE8sxqSE_FKEWWsDDSUJF0oKBDwVaJmk9oFjCwUeFeel7xk7lzu7.Gr18zs_ax6ROvhKykhveukKr0gme7tUFALc0VC8RDGPTLN3NBJFO7Kv7EUlZMAE9szPd1H8_1bfRwvnFseZTVO6rUS4Nya1br_qpkHUCBKxBnN2QZ1Mz2_bBOSHRZbQNpXpw4LJkc3GNAqdx7vw90P5geXyHegKIyKcWkj88Njejdxfz8m9AaDSmhrlT98hEsiKJViFFuj3ki7gQK9EC",mdrd: "6Uk_uhCJCb8UNR3WQjb8PsMDTYgsu4wlIVGHzejKdXY-1744169038-1.2.1.1-79xcQPQeYn9a.C6xIC6wlJkeXjibFBEshscBdg7GRvxkSPUsLFkANJo.CZV4FCgdXi7xHhpXd6YXfv_l3G99Gs4IuuAAf4YYiOYGuTOtgC7wk5UuitCpdmINo01xawxtjQRTojD_PSLRMO7suYTXCPJPPR2uZqbwmYEe1TV3rYYMRtxETUqqzvknPfo2vNeuok6AtyzQvHtTRB7BuPE84KHFQECfSxpYjnTtRJ_JcEeeDxxl8sgfL_rVK35Kjrf1O0ZrlWHfMFux3Nur26dcOCzjiwh3ixrXorVHu.dMXzdGJuwCSl0BWT34oks_NjiE_SqcA6S6x7xcniliIJhzEVPjsi9QSfh_rXF3_S7EejJrblG205qlKCQNTMBxUcwML907jYB.TmvrctRAdVZc3PfEp_I8cf16vmwf5AMwNYvn6SBNhz_9iAUEZWxIbaKhKaR2rjvOmE1f5SDzubMZWqAhctwwUbjiSKgMFntQ_cXwBbnFqRCwbqRYCzTQcsWWfMvw1zQvmYrix7EnNh4ShGWQHPNJ9h.vQI1UiTlh_rNzuBf.yxNwWgcgPmxzk9hdbsGxlUuI962NhNNcZMDCpYIb1F7Vs6DTydGCYkECnbY.ZNXZoSOY_ojpvFqIMZOUSkmMTTz8cucp7lXgtMbBm6yv1gYhf1mVppsHjKkgHVNOzV1x6FAoUUfpw2VJqhU.LTCA_QbuPq3zTH9OLwN_8xFOWZPj.YWNhjpdy2XHQhi_YJAUwYI6_CLCv2ngwiF6d1USudwuXvjzhmQfBUzWIZiOZy1M49VKAR56bxmSpSknHdpyfJKDu23l5LlGs_d6HlXlMor17E1VPwqxDQAJBYYb.ppHlxxsZLi6voBsUpe0Y8Yxy0irsY_5j7sKzWxCgjWtgB1mj3kd5HcHNXFH2028dj8focuK44rqWzpF5hwfts7Vu9mwlxtJfOg3PC9DWNRyo4WVBAZYyatDC1Xso3KQhKXjTbro_ZxGC3kUfHufD24R59.9nvqsw.wLPg079v9ZK.d3KkmpSyD9DobadbABfkX_nM24Ex3uPTlcHK_32SDpziH04S9y_9ZO1WgRN6ElOW0rqLVPs_SgAcAYjXt_J31kxvnUlS13wDQffGxPIq5MZe65Zpb_RlHjspsd2zBJIsSdK9bNwn1mZAO.b526b66L4ebRh1hxR9mOBrJafVOjDv9rOUofx5DlZtNhYRWIj8bnp0kopgAsh1LVqb7yi.DLJ0vXxo_eqVQf2AqWl4lA0ckL0_HRROKanwWkeSyVE5dBw0Knixeo8dft3cda4WN7FcLa5kZC66n14anVso4toqOCmWWJ2.1ETmZU3A8HwJtqL_TeGJ8.gULZbHUR9iSQ3mWFeiar2w9D8AWL0W5QYgZj.aktQo_L1zbf8vTLl4PccJisoGkTFpJC8iOM5htMFjdaY455rb0nPJgTfs2hhF5y0ghC4cd0gpehQX6nxH.dEzoixheZRSvdV9TC40nm3eQkJ6d.WPfIObQSYz6noy4OzyObyAfaoSOHzwvsXF0VBD4Hrncbdb5bsSEpbBPeudidImVhj3hsgBQti.V5oRxCc_KIn4qiVnDGzpDMeZlMiLnBzfDlUWb8hhp8AtCtSETZT6nfitra65s09Z6g55PhT1XNyE8t3L0eEzPBhpDpDUO6JJWnP5bQTXa1eoJMg7WlzOBkOUDqA_xdHsxlDc_R6FwtTbgL.XhCqbkbc3XzQZ0aa09dvmC1By02TnCJVN4X8JgsQxWbtR6NBa5BeQlLMF375wkq0LNCTpUQiSDk8PQrO4yJk2yT1JQ39vIt0bnEvLQIetUNM1L6AR9qKLvIoAjM5VnAo4xjvINAh.M7B_VnJv27woKuLcv_E1IWgUnY7Ne.1iinkWJ0SATa_fi_4k5EVg2p4KdR2utmLSKFUFkctQVZHgZBW4T3wfINdJkj8x9pXs6PQoOCuJxfU8HB2hrtgLoKDUuYngmdViR9kKOuxvRFypoUKIY0oS0mf_C04PolTddAoqXR8WMoxNQlSZyiTN8G1s6_"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d6e38d4c87a8f2';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, "\/1448.68431?__cf_chl_rt_tk=LIEujtTQ9F69_pbrc3Xm4MzD3NwJxA0CtnON3N8zhWY-1744169038-1.0.1.1-dV5EulMYwFYwvepqbX4a9P7IDtHHp0OmXvvBi2fYMts" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>