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: '92d6bad63dc8ce86',cH: '0B10oVtHJ3w2noTDSw5hGBkV.IZytHg8jJFqDq28F0A-1744167371-1.2.1.1-HUzuzA6XZ3s6Hm7gVGZStrX0TDGp86_F1rUzlfKJWSdThsEiftOE1J6nkXjuOil.',cUPMDTk: "\/?q=rf%3A6397212&__cf_chl_tk=tu7N_SqVAExSzpV2FLU1OxgLnyDJzz9VSZ9o4Wiwh6E-1744167371-1.0.1.1-dzdQqGuMgQNZjuxvilsfkrwQQwT8nwxtkspoy8h802g",cFPWv: 'g',cITimeS: '1744167371',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/?q=rf%3A6397212&__cf_chl_f_tk=tu7N_SqVAExSzpV2FLU1OxgLnyDJzz9VSZ9o4Wiwh6E-1744167371-1.0.1.1-dzdQqGuMgQNZjuxvilsfkrwQQwT8nwxtkspoy8h802g",md: "KWxv2x4zEQekkan9afyBGwE2MkCdlt6ZNLmI.PYSyXE-1744167371-1.2.1.1-7kiEIiyZ0LGIJY6.AKL3tr1Ypnd6qeo4TtdjqwviNnK3XBvdqGFSVRAy.7iuBtFB66vAMuaDT2pahUJYCQ4N42P3Dd4Vy7WdqOTGeKqT8WTpVnuUIUih5yIhMdJOMoJ.6NqGtweqC_jPprhsXM8Ft0nEJXWGKYn2scrScObDXh8zmHkPKOTsKI3lKsPNuWFnQeP_CPMF4xfofGmecXV2GhOhvBztJg9Wfs77VBeDwNrA.YInd9RCvuL7_99jzsFXcX6RcPoYLesLj.gbIeQQHBJjs32PJWt3CcC1ZhuyqbeHgsZrsvJG8bl3GlLpn8zs3OmclZy4Erj0pQqsZ_BADZJ6wNR85U0CV32fhXR1Ie.OHfitPG7pcjWmgam0KS_l23J9nuZvDutr4.hGao01RMd_echqsjoA5V7nIV38HQKAlZw2VEpFjDtNT23XsfBJWZQ5H8_rxvICGQU0r3zwsIfTHDhQSz1HtS1ad0LGAD0w6E_uXrfLsjGQEamdRjiRXgVph360J1JvaG3By7UpShttp_WHokg23XgP9bihpREJfRq3NkGpFnGdoXZsXsPewL.QMwN9rrJwo4Mca5gzMcLu0Qfk6.kHcJaywig3dKjNtQnlcqyeDzzqVaoOMzIWTiLEuF6X3_RZyWDy4S7V1Hok9.rHA2yMIW._k0E1im221rApentipdomsAEWVlf01pHux6jcM5Umj0Z10WSsQe_GGZ463GzUbxrP5H2d_Rz1HkrF3pqh7FNObgj5moQxh5Ez4PlZFSXPwvEZA7ZT9CEEIwWWbBPrYtso19HBYTgFdL_mu7mQXK_D_BaYEcFPKnXw4HMWhRi4jP9gRDt31e5p2G4JlUU8HO8CjplT8YcIuTd0rxcKQjpNhBJFZSoWZ.q1udh6_gao76n9cqCbKB7LXC1hwH4zcoUKUj5CAzKE.knec4nfrlvdzz1OGWrqvxl0rCtRpuNH5tPYR.rCZvWs59qNMJ86uu9F6qSlIZk0rusyXszrBRuJ9VueIEbPQ5ubTj8E2EIKRM3raGZaqSxXW7bDVQHD2F7U6c.GnyvJ9nvbUfTKptv0SKzNOTq_1HlV8zHpdXb3IMwEBtktGtPbYtNKEjSN9zmb7h6IpBco1J3kNWLtd60y0_z0uwpgaiUErCuHbc7s6DsAV.GZJAbJqofhuYTm8w4HtGSglnmbQYrTPlUBFOmjpcjFIton",mdrd: "rRDQeZGAm_6Lq..sz5mk2_LzSS4emI67an1tAtDC4Ow-1744167371-1.2.1.1-wgQ.jFT1TLlVUNHMAjPBJrPVKw7MZxM0523TXDOBSb9MUc5DXligwXBH138wZlXRkezvTqiWsIG6JAYZ7S1ylR1TZbfQApInwYmq99n.5bXkP3Ys9uPJ_u977qmAudx0Z4F0MuP8EVqLX3k25vs2O4vVsCE5tEJYj3Ep7_HNKKUQh5LZkTq7TER_zkdgTa7x_wM4yM0_IDJYgkAquplroHYH3NExMXrw6Rh_yStzbPmff90S3pRTFRuWwS68LAVKZc0NXJo4JAK640S9ZUbQux4X_ek7HIYGA0B.GAXtMWCI7XWzl5UIMURnp5kcVABeRIO7xyQ6z0YwAwZaijCeCLelX2leqUe5iW2ebGAovxqxzzVRMecI.P_WebCS.YLIsg39V8VNjGu0U00nU3C.BqIfOR2a_Pug0doybRjdzVGCCHFSD9k3SZlLf4sPwedZj16glkJves2WVMdVmKDf429fUmI4paOFf5qWNzR8jtaO_OuHB2CHjVyxMDCodVFawIdQJT1Wdw4SRn9bTqDVJ4I8bh_gV2e36mrCqH5iQh84Uupx3qQSfHEu5uF7Y3NFSAhcTF6WAzOA6vVtLP_EetYYSoqdGajs8JIYpCcP_6GAttljAjrickP70AwNwlX.INWKyObq2zKSxerTaJGt5mFby3GHIKGvuZX5N65RKr8canetpoNX_0wBIr8jRQkQLSUubyEzjdDepK.qDf1Y7Todgmr93H2xMM614u9dl1OkzDICdpgx4uUu9Hd7E1n4wskm9fwNKG6l2kYXP0uMWbH8ZFXWmqDff1hcuX4egohDrcMPbBVTYfKsHLGE8m.jBlZbSM.UjUI2Ez3q8aBUskqOgk0gs2f21sqy6YMk0kmJk27KvDX1Htc8KD8SB.f3zgwUDhKcS2qmXsJq.AZLKxxumzuvQirpSId28.2OOx0qkDZVsIpo2vofKZWMn8q5JE2SY3LtWcesqbN_tmiw4mSbgDoB0.No8VBHUWtIsJk6mHgNS92aQEJ9krIqyzvYXeAMRyQACqL1TIE92hNkxTdcbu54JC_2yvWg9zrogZlVUgAYLgH8H6AW621PXHAzTXIVXjo3D0t8ZZ.EO.CRNv9fzX3GBG0GenND73aQ7Odsv9xgOIadE96fuaOG6BTgGrr.TGpyOoVcMqggr0.BocEnxKq.8lBdypEfgOT.5VSATOnWKxBALGqG3q2KelTpTEklpbjLPHOvU5N_4rmeaG65kRNixAu_ha7yuqj109kvrRU1aVz0MjXy_DVRxQVBUVI7pd54l6M79QSo4yfb1vzz48fYn_VICp7cDDkASAX92d8Kk8JoffF9sxKOSjnmu8g835iiLBHe5hoNo4.69CO403DaMczTdPIuTMXqCzTCnIBKk9WuUSh8SlWDWG.sRW0jUpO833TYFVMjU2v8z9iAkn4RE_XRVK86O7GKy3FLfcFMe_pGq2uKq.fSh4PJralHsGvpB0l2EuO20qf8hQRAqi78nT2SV1aeFrLSa9LWPXRcKiaBtM2D9zQb29uk9RDUwhGAPL6KJqc_XGpt8KE8AcUBF7q4CRgbJw9pUdreDehaZLJa9Fwx7x2T8DVkVLd1K0wtGcpdZJ5WSM6def.TF1UZ4HlR8N2Xx.5T.DexEmd03QKr6rgm3ofuSi.owlNfEDng.aAtjKFqlA1HVeHH1queqJIS8T79n1JrXZLLAuUJcDlJofwXqTCe8aouggbb0Mz0Ve3gLgIqBPG9IlTB13LWWNPZZ_GS5HzA61.utrViq9Cw8wzSonJTnhiqn95.8U5XUpgejBHckt9mPvHZPZOPZD4_AMy7.JCCTNjet1n8alqwXCC5Ihp8AP4ty3GT8jDRcxsTfftGihGkIIDcdxduLFNVnKhnRF3dTZIQgJGj4xS0POxr4tl0Ja5WQFVVFe4_pv9nu7EvPQ67liyXldgYwAfXDfWw.4TqoQKpMknuzRKD.NRdatKn.uyRGXEV8ShjtFQrEGDXQroCBAczHTG5.yTD7P39vkd14eAlrPNia3CVEcvoWEpmEUoh"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d6bad63dc8ce86';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=rf%3A6397212&__cf_chl_rt_tk=tu7N_SqVAExSzpV2FLU1OxgLnyDJzz9VSZ9o4Wiwh6E-1744167371-1.0.1.1-dzdQqGuMgQNZjuxvilsfkrwQQwT8nwxtkspoy8h802g" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>