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: '92d99cd90da94102',cH: 'pCnpnLjkXFUwmIIPHTDN4A.w5gluutFUFbED2H7Z3M8-1744197600-1.2.1.1-W4EBdMBbDfinwlFGYsUqALkA1BVzGDEFd3poi6MQmqyGAyrBjMGbPKls1Kd2z5z.',cUPMDTk: "\/?q=in%3A135256&__cf_chl_tk=uHDgp7KYnBT4rnMeEFIIVviBjNNOq0fo_jZT0tsK9zQ-1744197600-1.0.1.1-NqIcsEIFT7msurFwxzDsyk3xnx80tXVqoQIW51SvCCY",cFPWv: 'g',cITimeS: '1744197600',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/?q=in%3A135256&__cf_chl_f_tk=uHDgp7KYnBT4rnMeEFIIVviBjNNOq0fo_jZT0tsK9zQ-1744197600-1.0.1.1-NqIcsEIFT7msurFwxzDsyk3xnx80tXVqoQIW51SvCCY",md: "ZHiaqQOcWCkulBV8FJ5P11gyAJI3mI0OfKS4k9JhP9w-1744197600-1.2.1.1-llXNj515SofBon4vMv7zK3tYASf4T.yvYL_osZI2YkhFiVWQr5BjMBmWbg6OlFMTlV6GvRskZ4ThfLXDIMFk_FjO9Nbfry2rB38DXTIe8.N.6T16cVpjxmDCTBh1s0eKYfg3zJ_tZfr3a16EWXhNBPWmN5zXYHyfu0MkvQIF5g4.T2evuPzC7xpxiO8BwlYfKDLnJY391Yqo9YiPok0pSWFexo2G7RL.uDgffWvHgEf6r2EWvtxb6KoF9JW9xGTmp._HxUBaXj9spkL4TdwHXsB6_IiEZ0nxPkLvMJ5b_K_7QJGdU.dkEhZ2J8LGGiDE33L4pDRTuKOTL2Xc52zyIyTUG8Dqsio7K0hXwnmB_Fu5.sqYVJA7RmnhsjOV63ye9kRW4141ygFxL8DrJ5i6f4KLRyaaKarHsne8EepEvqssmADT9EuLNCaAeV1zWq2_jkJiGs3csseZ5w2DfiH6CFazb5wKYD0lgcl3ZOCT5YbcIgupHAlBLlLfU5FcUalrzzo2xnF_1i8LaIFX6UV7MHyZysdcmiC.LsSARqOu8KDhlSwHs_UdONBp_SnXlL8fjyfPJ9zaHifH6WTpuVmi99TlxCGhF2JhhxOHmnR9A8hQAG5m7ueqfhMUNxFK4n.CDf3gnrpFDuQMolzd_r4izfvZ0XNudlPRo9OGYq.I0FXxbxI1MvZI5_YbCstmJF8nbnCj40C3KIJO1sjsAbYPtrRcD5fKv0o.0nHWqfKqrAXNSP2cIpMNSzTlRTu68ttJrcRCuPWzFSE..q5YB7dnmX_X6iEaqr72Ambn2BnIzsnCOBD141rhKJ93J2iT5swF7ddLjHyvfDsqIEIG9pYDYNmrKOJlO4POYmI96q8Uru29HR.Pxjd08sZTIX2tL1QNtE32dLmA7HggtKPmNvn8HqwDZjynSxRfYQ3pt6m8_.DYENc6nvPBfKcbPh_W1ripMs35Hd7OiNt7Pb8aVjz6c5Wgr2BtMO7ze.x2vP3e4e.fquK_DU.9htbFezBz2rOplMV9283.FQZAHHC5lXspOYw_4TKoNO7zqvE1c0FYSnUustYzg.fn4Nuxzn_Xd9T854zrsYf0lAla5QIkVL1ce4BpfZE4aCamQF5IEGEkfY2BWERDQqRiWME190JNbp50Ir3vXn9MwGU0BpfZfermEZ00VGwbrv_PvLtHdq3N.H6jwVawBpXl9cT1fG50HVT1",mdrd: "Pxgfh_HTjA7zTOCuqyZAzswzBnk0Jkgg2wz7tq7mW2M-1744197600-1.2.1.1-SIWD8P8t51yWIASIbsSoOKQqGbGaftEAGg0yRq5vTjmtE7hdgNYndf2fY_Qle3yHeUBIw6AZa8pb8OzBdEulUpvNpIwiQ42wA2G2tXwiORiA..qBCgJHd5bngKxY1bvUjcGxpxB9oGv_Aq0_1jWJ.j5TWlrswxFNPL6sGnNDiPWMfcw_clPnEYdOa1asVxA9smrQNwPzwYyTa2dPBsmIWuhfo6AHygdZl6A76oDAIl0tz3gTx6g_eN5fk9PAFvjzoOEqXHnvUggew7Nv5H0jLOSLewbGULYxGgz0_wYKvHI.dGSB5juBhftZH7FAD5orOrUe3fsGWY1bixAYAs3qI6D2V1W0QHh53f_sRntm.Ue3IuwPpiISBibPstFZ136oxbaqV_KPXceVmg0dZueFVxKMTICDKTmKetwqFYCB.iYrdFZ7F06sr6toGoMhAQqMsPyViqqUndPnoXrkO36EA__q992IhEPCJ2JTFiXfc4KpjNuNWvdpsau8pU4kQjJnR3UQcMj5NyjAMtOtK0zJzdFoUgfQrVry6Fbb7LhNk5qWKnel6pRLYd4F6h1TCktLtHIUKFqO7.CDCKEvIm3SPLivObzlfREVoWQfZDTWC5MdkxJidaDHEh9Ympg_KyQKivwvVuStYL10qsu6SSApZASkcgOoZztgXRe78nrMf.VjjJ0WyOjYT4fRSX26Y_MLcKUmaZI95cuNC88g.QianyiPb416vN434BDfimOinn6R12l.JUWz5N0btVfO.D7gK0eGB00ynRDPsBTi9.pi918JRT7igWm3GBz7ZSBG3UO8B9vc8JqTW6DWkCUJVDlkphZvoDfu1ppjqTRr4Hq4LgVvCy0_4VEJvIJX9GUAM6uE.ZbhCDJuFYdjujIEl.Yc5kBfPHLPidrckurG_aTlFJeFLLxBrk2R4DC5t1.ZHhZRy4cS2ddhhfXMlm1ImHay5q93PR5q6pdR2LygwgkZKWscHepHgXCeNMRth5w.Fadh9P4MPVVLaE3I9JTDMKro58q.FsnnpoJvUfOYa__RdNrbFNBfR5XQSF6usxFOGP.jecQsXV3y17WC9e8971m_tVb2g1fmTA3uMslMji6xiwgZI_rBAC8RqWVL76tEg6ZgF3o8jQAfXR9JFA7.GPF9bRtnDUQxOFyT61ZKMGeICuHtavXvnO3g_1FVhKWHMRBE7FOjSkuvzQDi7kZEoJmWI1_tuKjD_OKG4uCfIDUz8WIBE03kDClzGZUcdcWMjZYSWfdZb8BVyA9j05CH9Jl2yO1yHi_Z7tjkMzeNa3S_r3SSczBWXwHPpcs4cfw27FzwAz5dh51nVYaB0QjsEIKrfzJA.M3NsAtzeRWN_fx5wzoW7P4vh0wbwfxr2lCX1iC8jInNH2BatFSLz9Hn6f0JRnHCYv5gYNfosGyvWMQjyrvzhRMkj5y5J3eP_7Dsd1XQR553wgt2wtwPzMQZwIRLzip4wTFnLd86tGYtRDlfMVx91Zev4PxG6wCKB5k9RGw9x1FJDFGssbgg9ps58b..JEzV64c1wMwY.6UqAqsD40Db9InPy7IatJy1YcM2jHSIGTJBZkupPjbpEze0qed9_KsZOS9qD6scdTQ027In.lZlDC5q3xtowIo6Glr5Lgs8s4R2OPtidUPt3biqDjW_swXhiK2Jx0AjqR63NkpFC0ovKLWnqS5pXjbc5lCG02e5x4zdGfJdyBJZaB76YQ0nFgj6gCL9w_n2T1YeqkWyMV6V2fna7trQsI8sm81GP1.QES7e2j2AUYmRzEPFRlyzeHhxXsrlvp2srlQZIiEJQUKBmU4vu8N9nzPqEXIxqGXcmg4dv_IIuL0lEPaXb5rXsxq6VTCq2ndCCQpvgPPtOkKtjmI.2RVRyzTJtbuhvyvSnmBNKsbmefxOC10ZxcyNeWodXuOrMZ7vDxmr_IRxEy3EzMaI7NSDa6YQSmC2o8GUjsijIMjE7swrPpQ5a14astto0_x.Vf8ye0nJUkOaMvZNCz66.WNe.9DNREt6KwauWBHFcY3Nd82VswY42FwX"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d99cd90da94102';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=in%3A135256&__cf_chl_rt_tk=uHDgp7KYnBT4rnMeEFIIVviBjNNOq0fo_jZT0tsK9zQ-1744197600-1.0.1.1-NqIcsEIFT7msurFwxzDsyk3xnx80tXVqoQIW51SvCCY" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>