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: '92ed46dc1a699c33',cH: 'ggpvJDblhBgOmOp0vhnNp833qVYlzyCC7dtng4klnxI-1744403793-1.2.1.1-plqfLIv36aX0bA4AMay3oOJa7C6ru_SgMcmYObY87ygwwlQF3.TRATmNgtiYlujp',cUPMDTk: "\/7973768?__cf_chl_tk=ToSR37O4VrLS4y9VPn91NWGt2KyaqS46FcX5hD91BZg-1744403793-1.0.1.1-6c1SjN8_EPYA9Kfo39oVIQ.LmNOvwnSkDz.GOjzqGhY",cFPWv: 'b',cITimeS: '1744403793',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/7973768?__cf_chl_f_tk=ToSR37O4VrLS4y9VPn91NWGt2KyaqS46FcX5hD91BZg-1744403793-1.0.1.1-6c1SjN8_EPYA9Kfo39oVIQ.LmNOvwnSkDz.GOjzqGhY",md: "vyGTgENSERhuoIM9rZtV0s1PkUTlkH1MSREefjKOy80-1744403793-1.2.1.1-MwE6YUBCpl0mC6PnC0crlPPdGYpXZoVh.50clF4i7mngDx37XXOnpPtcGOE3JDZfdcmHoAyAPkSjFwDt7W967OCBgJlKwvAV0kxU5b4Ub5nGXGoGoESK1yXENKqC5zYvNwivNDi95M777816bLAmCwMD.Ee1TzFPEoFugiY8dO43v2McsUZd42AnpjiB_Mw9MjybSLQHVgGbJUp5tLUSVuu9UckmT5kmozKotyF41fC55QoWjUsDIUmlimeg_8EcRQbxU4gn61luWkFL7gi.fIiXTN49vhpZtSDZvAhntdZ8Xb9b4EK3dLv1XktdcbsBtDfFWBZju7aKGeOIHoFcl6FX5KcD9OTZp.52aEZ6bs4oo72MkZsXepiTWYAOu8.wnPPtk4OS_Z1VSmIzBMSGXWC954sd4fy3DKTXVwGL75hbwEWpxcOXkM.9AlvYB2V0cO8WG0He0RYXARn46RcmzjtHXhKFMdfdwfDKxUpixQrho3R8nBhaQnwFek5YiRGOXNdQrdZGf7h69tGwfUlUZ18OWThzeoFEIy.osBHECbVokmaH4gckpp4tOD_C4paNWq2068OEQ9KlsoegeakwHTUJTk.K2UBB1SQ6yU2JZA88zsYSV5vlr_dP0wTCGtSIEvjfr7nbx.bACYAAcWi1gwnfKJsat6eWw6Luc1LwAtLtHhsmbHGVVdbOJuIsFE.i2G._NOeem0A5hiDg3kzCOgJfzibtn.Qgwfb18bkz_MqKd6SDawOpyPALDMEHn3Bko1qwzDlKPo0syJosvscnIAFFJ8dwvWLJQcdxjaEobeA7UO3hHQJ1QbiFo.Q_q9_PiMlR6H4vYVUbbK1gJCGXqVrlmbMpO7l2cFChK6.nqsMMLRkSJTObs8G0wjt8uiYsFwy_N5QX4uh7qnL3a7aA2u5CDciLURlErwOu4KBsE.JG98RIxb4hVbBbU8t84nsAQrswihsnaV.ktqWZIWi.GU_gWbtgkueGib2Ln_.bahm3MFlHrofdE9EvDjVZIpkhNEEv.Se4eAdcTWYo2Q7aAlu0EkmuDXFZBy2.gfzWLC3wtbArDcg5.XcZoREnYn0GqGZmHtG6YAoE9_x2qygFdJswQAkBLLoFnXDZKM5CI5vHLl5BBYlmJHNpbFsHfe74aXjVHDXiheYMm7IyXOw.izQWjLDbjxpkm58YetFuzKY",mdrd: "xOlM0ehjrdzYu2cq4TL_D2j8qBsWInP2s78eP5eVO58-1744403793-1.2.1.1-wZ1Q07.HlN2Kv2l_d.Js_e50YI.I16cotyAlXwRad.tQue1BTKqRrzaqeyoWAVVjNJdIC9jmSVW0HoDRmZnuHMPmmvPDiF3f.ilsuqch7T9nj3jcUiUnQ2G0q6ynlgr1MF6RxGTbf9DIbqRJ.OzS2XvUo.as7JXp9P4nyWTUNVpNynSBDHhdOKLceU_urC6OQx4ZYoKyzfZbGIsYUKtGW88zc2vDkZg3lJM18kbLb6kJ4JDjSZOEio7VfASObE8FWxS0hddD6JI1eExarZiaD4q5i2MdoSBWWicCX_g9Kwe6EggBD7RbU2YEgCrwywX78HS4u6ZEwh9PvnWZ.UwrIB9IFg2swVTKXwmrSfaUF0Q2Hj4Pn5WA7R7JAsckHig_yH29fRQwU_GszZAyuGCSuGdwdOvpi9mZMn1KFuL2rNgB62qKbVURsAcCNSrZ2NjZYtdi8z.VqrLZ8XBvCAG33a8lu9yIEbQJ.QtbU0p2gjrdLfXpvk1AYyr90_P9nVjHrpyeOOHs5jBQZfc4Zul6qNx7kmFGePRQycj8Vk1sZdD3wy1sHo6DsAZtAyFYinJnSZGYBOC_UwCk06CnBcXxjVS.BTYeZgDYPR2uuiE9IlFmg4QeiV_77mry4jyaK1if6Ieh_7iqZJUyG55izVHIAL1H045f.uEx5smZe7mIUCgd7PBCvXBNMGiFPieHV_vDr9Nd6lMe91hEkbdccraun_V5EtJHxSPGKSTAVWxTnnVkVLKV_4bqDWB9EQsLQdhoBOqOAIAjYphpQI0wRCPqZbYnUcpcKyRoLwsQtgJbk8EdjTXs_yJLFtLXRxWoWVqJzkUHebpWCmGaYI3U3PIijhgBvn6PQ3Di_xujUN2TPNZxCLBwxB19nIXdX5yZ1FALq8t.BDcPKzuDe2WHf6xedmOd8.JMxWIipAMmwPWa44iXn1Dd0VzJyEr6bDGwdaUFiTKfL7ZXwE0yYdE3KIObrHefKaqfzHYZcXLnrDNiA92RjIDGbDJyAl4aWQa8.dAw.rKSsJLFgT5Gyl_2aFWWy9SYEbZXmJfn26lkEa8afofAP005_rJS73wfdt5Ub5r9ewUWBEq93i.PStxoXMnXJDBdxuBztlxIyQE7WTwTd461h3ET2dAcIu5KGpEMhGy3HEq8aRoFhO2PLYDXZAsYnWZEfwCAc5amq6uzI1RwRoTOn96SfhoBO3zYqFRuqzOB_JF3OxJSkAeZ_0bq0HCl82pyTJNbx9u8HuBilczXhn_8pIUCtNqILYgIRSob1cVrQ6qM3ZO1GJGUxuBTutcQ2JD0qxSgeNxfTPvM5P56yPSe9YQ5LIPH3qPF7JLLDClRBq3vt85PuM_kllU6mzXYRS7qSFLW0DWRSgQFwD0v0P1QfmP_OQ9_R6ppj_yATczBHuFWPgpLQp7FkEKL0Q8V0NHzjMMpgEnPMlue8yY4qxvarvbb3nFIKCKymQjX.7sr0EHPYlPWj9DM83wssr6Iud7B9rAXEnWcAy2hsVE1n070mYwHgswvPwPVY6flxN23iOqwxynlx0rLcSnrMOpakygcPDAwZe8r8zrDsGDGDsIT7tAczBqbJMXy4oH3OZF0rJI2.CnH71O8VKuE..SryiiVUInNqHdStE.yyGF4R0WP4aFEqbAWpp0rPFmxyGJv7EUZh6jxFX6y_G.8M8bmf_.xzVHl_adQwXzDKjTp9JQt8rAEKZkQ47Z3FZTHkXsNIg0mg547PGHHSqrLMRQVPCkii8G1RZRrVwAmYSoeXNJn7vjNzbg7SggWfs3.PK5EKIoAvi6T.Ik25px9Nl_mwVWHSLQbpqXuhgFAObgZF9qj1XLvpqLXnntuSP548ObB5SZCUFjTsWgaaY9BAeZJIrU.aSMuRiFaMCqNPz.XyTsZXNOlmeqkeZsBo2_cl9mAk7rkhql85JFC6qHwISm0DA5mZGl9IPaxTuNGxE3iOYEJiWr6WvwdCfbrKH4IM86z2_RLlqM.qZoBHG0zlRzUI8FmVnbwZ.illWEUx1vZGl5gacTp5bZPkoucGn1nKSl8"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92ed46dc1a699c33';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, "\/7973768?__cf_chl_rt_tk=ToSR37O4VrLS4y9VPn91NWGt2KyaqS46FcX5hD91BZg-1744403793-1.0.1.1-6c1SjN8_EPYA9Kfo39oVIQ.LmNOvwnSkDz.GOjzqGhY" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>