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: '92dad65a8e36294b',cH: 'koaSZ9yJe9gfe8663GV9Z9mUSryMAYVwOnpaQ.GPSA0-1744210441-1.2.1.1-qjv_XUYF7jM9rJqFgQ7go423L.ouE1vCGapO1PcxcV2u6cOxfoP48CzqlN6_jcXD',cUPMDTk: "\/1298.93283?__cf_chl_tk=tKvCGtrDKLahngWm9auDbb_48v7bXI1eYsG2xWrwmrE-1744210441-1.0.1.1-x1OLhMRnQRpwJDrokeIYdce1EY9q0rw0SaQFCpWRCYk",cFPWv: 'g',cITimeS: '1744210441',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1298.93283?__cf_chl_f_tk=tKvCGtrDKLahngWm9auDbb_48v7bXI1eYsG2xWrwmrE-1744210441-1.0.1.1-x1OLhMRnQRpwJDrokeIYdce1EY9q0rw0SaQFCpWRCYk",md: "0cvjJY0tOQOEyvBK7ZACXmOMmdEw7wXFWSMnJ1WY2HM-1744210441-1.2.1.1-YGbBEag44SkHxcljnQc3uJsQ6qEbDtWwJmkdDGsfWVh3sTz2V0QmGN8Bb9NoqU2SUe66LRvZZc0XMtrBeV5uzKsSGAkXLOYFvqwhElL9vV8VIroHH34CNCPtQN.9cum8MJulHFpryVP6VEZ6t2P0BmxKG80UZvkfH_yJ9bAkEJvsliymSrWfCMnVBX5LLLH15jP7ol0cXusoU.EBPLLbIbzkbB98D6UvK0VoNZLZtvrm0XhmPHnBNUKmfDAJtE9W2NZ2Rs7GGjPI7NU37YpviaMWLHrqQnmQr389CBV7B6vnKmiE1w9CiSW7QUvwFxaZtDfeDmg.w9HspA3NfyoWr9tth7gEnHs_gDF0zoBlTsJCiU.6Rmn2HISjAMxNTDVkg_gwewfvH5hfp3XRAJNBErVmzePLYCaPMChQ5NS34Qqj9T1VnouPiJYMmlSRVm0hKKCRDxoPNeZQJaBV28mRtS.csm7zr6ibeNiWVrYOvLjCBa.yZis_jezqs8wMT2m9VmeT4l.M383XdjFZV7zEmECwtdJN1.m6hS1wU.kei_e.sJ_Mp_CFIYa666V8234bBI7Rny883pYFTjZ43B0SVG85t5m8FZjC3HDa19QvuzjPXoF8Eh81ldWthjA7G.A7ZRT9E_F1Gypd1YIhEDHt50wrWF0OOaGUOVz_FiHRGKIv9c0xdB9i5XMI045cuB5HJ6to5Mb5AIWBr.kv72ZlUvWOcpxsoBWtgOCJz52y3CThHDa50ZzS1EFqBqfhDD4rmKVL402TTTAL2etknvfEut_vSaMoYdpFkwPtN.9SqqbEytFsWUx0FMtJZeFWBXDaHtrczXte0G_LK8n72brEy7jPlco42W2aWIeHiB2.cPNtGuj4fvVvnMCtmHKrtp1.6TNfD2sZzm4jUW9rAvdS9ppCm4UqOT8RZctOezQjVq4..GVTAyCA7hh9fKB2BfO5_aiufY8lkpscqgSoklVEp.JYG0qc3CLM1GPCuu52sgi5pSnQxARuuu.SfvRdD9hNAmPBISO5niGxTLo0r7ik.Ay1gUis6Op7KM5CJgDGlFxGs6rPzerHYGLbfmgthAHifGUJ9LAwTGKm8fkGSTi29z3dDhRgJkVYVJqDYtH7JNQ.sVzx2AKNEqikEKVbRGaNoK.VtqTaV.t_wuuSs8uv_IO2XRC4tHeIZleYgsPalM.uxtOxm.hLOSTvaKI0tB_r",mdrd: "0LpkVTRKBId4t7s1cU_X8b2I9b78J4ngz8pGWO1iQCI-1744210441-1.2.1.1-AFEQYrRjF2qiwgx9fv.5jzGhSbPKDCDZEgQBvHgEiEVszCSJ_KGis9PF24ifer2ppQSBqzWMnJ2jEC8quO4OCIJm.tIhA6MeL5S8NqPQuRVlMpjN3lkStr8XX7zyo5e4TrDUKvJKBPKSAB7t3STMwc69GzEVFhu3qcwM4X8rPrXRwJrjFsLjLGZ_L5iQg0pmNe9mTXYQ86Avl6gKr1c1u59UmhVNIgw0fICEXEUE8YGpUI8rGvj780eO_vgSADppXG73iN0DpYwSX1pRL1CDmhDl2yBZLsUpi321G1zbBIh7nxtaD5smuVQoPTLfhWIuijFW29_lhm.DYuSpqN1PaTKYWW18E0FJjU6KSNKXV784N.PfbF79RoulT_VYsHUNUJTCS9RJuiEOk68KMQJ.JXqNuyntQi4wjfpTxKzCcj5B1.kdqUQYphczQnsDDSsbLRjEbws6LCLhYR7aKAvXWRrVUnSf9CkbXhcuHwda8aVD_ZVvJpzgZgcXTbg4mwk22lGOlqUzKeggSkEMcsUQX7MibNG3XbDmqMchx_MIbPYT7PA4hwXk2Wd7KTqIB9QsbvDJtU5V9AWZlSF8qbCOmwqSvMpJxgvViybC4j77lNYg_VXlPZvYD9WsjXCz9tQIaoy5aLvLyJl5xY_l_KW7J52JviCdN6VorWWlu.pbJ0RTjE0qKBPHs4kLdqjWPHAyHr5Br0dJHsoKZ1pvGwdK5xN5ET8S5r_fd_0TbxAej4MvZK4IvpDdqOOzkRmJTH1Y0HbtbVcDVCpHysNUxlYjzxOAFvAN1UplHkypkO8X2XxY0xRwUv.A4yH6gtH5uyv.DgIVUYUJzMHWZcXE8hP02lYWxJMLfrmR1Hzjd4SYWFouLmed0m.hmNN6NxQUcx0NCyWM3TePMChA1L1RptlzemK_8l5oqCbAVThuwpPS9UzrZaBGwNt4EXXpQrSBgbf2ImwDlJF6obqKkg1n.XlsF7UXyRhkuIIqXXNosmUrpiB3RAfu6e1q78i3Aq_aGMR1hXQuWsUHe_zNwzTBwojCoG.DtQGHvEDe5lIT0UEmq7PYvW5C7erX_7LKjCVB1QSsFirYyvnx9yn9iXuwsPMJoQBFc6793h2a8ry5PLC9Z8LnRrdU3Le1t56emNfWkoR7o1KtWTL6DKNkhx17QALoNBICPemryb.KDdKqJyKgdPwWwwKUAtR.eRHeviA1FDCqN9Y7otaQhObRfTegdUwL6W6bX_eSgEirhMNohQII4Wnprd_dQTJipwOhj6teSfMLVlyInNi7dvzxLpQzICQN5u4HRwror0mfdqryD7M6Sx1I7rDTJWnTrLv7qjxa0RouABY1ZjdQp4Y43Me5vZT9u.gxVvyoRtgjSXCETiwUJSWIA8FErPzu7J6dt3pgiW_7kHL00tpo96UjZqFJqgmcKC2OGUFu5T1hgk5mDhgp9wm6LiRSdJ8h2cZRKTf5LN4a3taKqP7CqTmv8Uey1hu2yBzYhIlZeBuyyazZqjc2.B6ES4bjwb8RdHNQC9QoYS5g.cVbc0JuI0bF0CcyAruXBliYoMqb7iL1jRXiIbkiTpo_AZzENx26781ws8Mz.WboAZ5LRA4fLqnDNvM6Jx0N4Ymtca6txm5IfnKIhUAgta0Vk502dc79rULktk_Jpa4N0FSgqcGD3SU5HNQoAZHnUekv2l06C8N32_.wd0dU6qS0qLpBXYMBS72ZfJL_yXrcgjGpYpQt1SZEKN0b2p0LLbSG1xV.aOZrDn9o3eJwXwrfhAj3R.FHmlb9BtWqgcrBhW.9Nc1zRv2ttz1ZuFSMgnAQjftC6uEEQ4s8P.YlKMBPyUWizO33HSwqfsHC5qzzPY6L4PLslFf03LF3GlhUrsq0XdDPLnbvfyX28MGZLMjrgooFA_sbYm56DRltgyGyKWaLN5DN49ILOxMwE7HZi6GargmH20_5D5K49qfbkYpTNFm9jpmC3.t5icUgw.1fS3ElJRfPYFLjzMhhezwchxoqJN19H0aZIjTHVYvxlrOmbEmZvdDMbwrAv.NMidNJSJD79_CAhcYpIKkTF22gYQ"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92dad65a8e36294b';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, "\/1298.93283?__cf_chl_rt_tk=tKvCGtrDKLahngWm9auDbb_48v7bXI1eYsG2xWrwmrE-1744210441-1.0.1.1-x1OLhMRnQRpwJDrokeIYdce1EY9q0rw0SaQFCpWRCYk" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>