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: '92d4b8507f9f40e3',cH: 'OYxKMxafCssxDRoR6f8rHhQE6JgPoQmWncUkXC0nFMk-1744146296-1.2.1.1-WCmNNxR2.94oNrafYEWYoeeXSnQiFbLNVxWmW0osThRRqYmgCtKifKub6AblW4uD',cUPMDTk: "\/1377.93005?__cf_chl_tk=Oq8sr3jn4Gc0pMbJN3gHIz1ZvKerBJmheBuHSJCz2lY-1744146296-1.0.1.1-8GBj5ulE3fTzidjiDV3B8TMYglxLAPVn4g1HaOCQToc",cFPWv: 'g',cITimeS: '1744146296',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1377.93005?__cf_chl_f_tk=Oq8sr3jn4Gc0pMbJN3gHIz1ZvKerBJmheBuHSJCz2lY-1744146296-1.0.1.1-8GBj5ulE3fTzidjiDV3B8TMYglxLAPVn4g1HaOCQToc",md: "CKIZsViy5P7iKJ_o.HsGd7T72aRkrNg_396MmdqFPAk-1744146296-1.2.1.1-Wx52tWdb.4VZjGwDDm7FhdfVRlfYbaqXyDT3l2l.OmqI8am3MLv0UbN9dKdEdZrS4fYzEB29fMa4djhCuW0l_ma2.cCdU3hnht1Prhx1EZ.hzezyPDOA5bJ0nq37WBibWsUv85aiwHLs5eKy2d7y9Q5HRBJqsW6T9u70LnJwY6Jw3ojjTElBXi8C6ljVgQ2FhtJEJzIkWxq0jlMGRQ4GadhWuUFkIaMtcDd4MtQOk_tMGU4bP1iH29GteFijMRU5OXdAdqlIiC4Hmt_LxGsIUss993z2yCTKMCllG.KZG4cHbx05o798oYru3zKKisKBzcatHE9NFM6oyyEGmy.7HnJt49dgmthOVwneuN6hgMgxIbRrZVc47BoCa.jYZV5io00QPe2Z2kfS4gz2bR_bWrnT7KRg2wr8oe6CZ7MdjxtWfTh4376o19rhpCuJwFp6U3OBARAgKEN56MkhF3LdKvm0N7RT.wtjQWAdH7DKoiif_UylomAdG310ri0t1gdly_v.AGusVFuxm4HiAkb6xUakgp2mqlBkhRQetT.XAeZeZZyRtH.Gsi8evgajx1FTpWqtRUcGz9FAYKgqZnnOkqPdZZ63NuRuhNH81np68yG_toVnWRu9V3LfKTudGKtSc9mrYijLx_3.Q_7qHG82dsHUkq2TUKkP82HOXNWOTCGyORmCDrk9amHweFSX.0KmqQzY0xvqYlzcpzdfkQSimQ5RZtCaZTdpxaAD4pKhL66lI00YcfYZA2.0Drb8Pvs3QCwlJOlmRZs0WMb5gQ08Aur9rMfkMl3ZhuzHnYzjY__hfTmivciDlgOdflJLKDMRh7IhbgCNrKNyDbjY9lAXP3wcglvFbfu0K7gVOctHT2E669bEjvf1gu4CDKOQ6HuFko.n0gLSS38uwJZISBaYolfwRmkxxHPe9hzlb8D0zCc.2p4RaAGd5X5PrjQiZxUZjflCBdQFOKlF90WbCeZQc0EXIs4E6BTKNlHw.O_iW2wzsA9hdDpV.go5kepW3WFmCZrRc4CERyrLyB24J4ZIyhVOgJkzsRUrbVezq0pqbZWLH2NQOTJlZiWf340dcmZO0m8WRHgUd6iWIE1roWs3I2FAvusuWfarJy58_wUEjmvo2BPsjZmawBIva27Awi0JVjbYjXwceyGxU30sbCMyLy_oDCqV12SgLW687eiAN8f.DkaWsm0kjpwZYuJE3GR2",mdrd: "l0BrJjzL3vKbwejNaP8Aus9IqW2gzw2k1_xdknfv96U-1744146296-1.2.1.1-qJ7hBs9tA0V.h8RA2sSJ6VNr.U8UPn0WNL_vDRFxAUHM8KwoVqyie._yRP04sQhuCHUTcM9TogQWS5qp58NitmMH9yxsbhkHrXD_UBua6If5LTHwW5lH5sqr5Q.DeR7B9p.O5vyeHTajc2azHx_Q.TcHt3SBoUjdffuz2ACniA6gPcN.Bs.SPjBUlcewPq9Z9vd.x.B5400SmuqylhveQtvwUDSPhBQ7h9Ef.CSp2mgi8DcV_ioWNm7_ekO8FVWwSag8iuen3voiGv6_72T3kDFA4bACYqXCH0vvAC.9Cqmrh0JuQHKLQCptLo3prFXEEaVqeJnzkdsFlr13HzrkLAlfjL5u.l8r0oG_uaetrJHJYBjcfDli31T9CHnOPQ1YLC_lZ9bzm2n_FN48gQlvl6qbHJcucze4Tb1TRKdK.AZdyNa7ae7PMli5bqZyIJoPIMq2MEu3YjAwtgQtQGjfKRL52122UYWa8k2aDRwUbD4znp9yCBWc4B0JzczXk1rDXfH_FQErehT7QeHlDYXXCYm86sY3ku18C147.sqTyvzr65jnWeyOBCug5aZoPI7rgJQRRwAg9KFYfHOqRn_pKVJoap45zbk9QyBbzcuHr4JxP.mlr7qCoJP964rs080bcFmYFw5o23C7gBwOOIoB6cidK7dOVI85Xm5ZCWtl7Q0vpyQyI3CWVGghhvj1UJN_0W5J8Da1k61od6jqBMj5lZREAk9Ci_M7yn3NaRMHbbe2GGhoKN__oG.eJgjWtrjpc4KrLjM8vjTe0U_c_2EhTjrmQLLV3ka5nsbIiUrOUyOAA2dIcv7NQ0xdfmTezA22uWV73LWGA1cu5IibcSCosh0m54rVWpTZveHishek2cHKIYguB.VvZ5AEQlpI8LRpeZkeJY_ch7GrBX3uDukKKQifyevGSVoysT8QJ0EHDL1zusmZW.GPS2WNux9p5fo25cZ9LAxMIIaB.Z2z5yQLJ8JQa6cBZpg.uLKa6qdSsGi31Dtsp2XhYvrcRoMSfTswngnbeGurnTuKhgQfJvOjlujj2MHN1b0O8H5kpyDYPL1GQHmaSr4dBbHX2jW_HXU1fExcETuIOZb3K_WIu0XSbQmincm_l.4s2dMVMx3EYP5rHTdTnNF3XV5M96LnMWfg5LPBP0Cy6NZFiTn8CdGscdMn0QrrfDwhMFMvxz9nJE085hLkRFY5S7xKkGC5M6tz53PzjuHuJttaUbrOeEv7o54xoQHLMsTiOLCXf_B5wjCBfLRsiH_b9Rbfio4NH6KzZ.1P0CpDDbfAjLBuo141_GteIB6igmf88Q56xww3BbMqBa.C29gQ5PLUylN1jHhY8OUnXIx7hINZ27g.MKabzNpnCyAbyKuLbOvVin3I1.hyvQbYczTX7E4ROItjtCcHHQqwMvYAeY4w_MzTgF5KFBVzfqgM_cEhTu4VD34_pwcCJj8MQZ7BkSItcp.OlhzHfEqOCjYWzW.LVBfymEsgX5BNNqE1OPCJPKf353Vsct7RGVOS2pV_mDpHRepKBTIC5T2H_vOTCtTUaJbxJqPoP101yMP41Nx1byp9YRpbXHv5f7NoyneReS6HcpBkk_VF8z0rzBVl5yRsXkJF7mB7RSrHlPwfcnlrzJC98_L0aNbfWMFfvPdb7Nldx_TVidZkNv3lcrWg5phu6u2NnZh6ELUXWXy3.DZvhhGDfh5XhbZJlM0fDNQFkCHlIfweAGpRZPf.bN.SDE6QIrqxnsdgf5mXOCCDX7Z6Zp0wCxJbznZM362nOaopXfnphCmcVeUar9LdcYGIwJKh4PgCtBbZuHuXB9fNX6QkGWCQ2Z2khTgkDQxpXH_vqVfRB..kZ7SaZ1zxGqQXv5KlHFrdrVGLiQ2Af3utEfF3voprR2DU2ZE6h.d7GpC4SsDjaDMCAhsnf.HJ6mTlvTfZcNjad3dLLM59nCaFm8Mq_oBnxy3hHzHAwWGRYCTz_Hn48r2ZHN1daC2tMLf75go9IvuSsyvT32x_A.XpnAslbELxRPbkGJb.rIDV5C5prXkGtoli7wbMW953XvyVt554Mqcbua.pLg"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d4b8507f9f40e3';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, "\/1377.93005?__cf_chl_rt_tk=Oq8sr3jn4Gc0pMbJN3gHIz1ZvKerBJmheBuHSJCz2lY-1744146296-1.0.1.1-8GBj5ulE3fTzidjiDV3B8TMYglxLAPVn4g1HaOCQToc" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>