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: '92d74bf3aeae5f7c',cH: '_YLCAg3mkjvqdSYjLchnYTguAut2XKXXrXjuEojYUJk-1744173315-1.2.1.1-h9LfZVyVJOKash3LeVIsO2j0JpvJGH9mQqTn9dRdf25qD_H8A054e7K4wU3q6kr_',cUPMDTk: "\/1513.26076?__cf_chl_tk=KgEHFZ4iqoS4WqEZpU2LhqHSOzBcfnfYZkAePTyPxuw-1744173315-1.0.1.1-l6QzR_EkENdM.BHwMwdN_6DM_fYgGc0CzmSsrW9JSXo",cFPWv: 'g',cITimeS: '1744173315',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1513.26076?__cf_chl_f_tk=KgEHFZ4iqoS4WqEZpU2LhqHSOzBcfnfYZkAePTyPxuw-1744173315-1.0.1.1-l6QzR_EkENdM.BHwMwdN_6DM_fYgGc0CzmSsrW9JSXo",md: "R18ZgsobfQwAp8CPDa.e9qv9wYp7lncCkVPkpoxRm8w-1744173315-1.2.1.1-oiIYHij_t62KK4cqs8tijIU25FeC7vzuPIK3YbMfLp2LAlTVGcnQybOhKp4QArHNSoqE606y.FVvKn7jiNOOT1Zmg.ghmdYcRBqE65mgnaHuJ4P9GKYLcTaw8OWXO0jRaoEhJY9afGNYlIH7Athzlu0M6PaAczKvcKjePu8HoME7bUQF176UssxUmOZYUyg8ZCPgFvAnYEXU4UfJYimLSB2v8jegq2u48WE4OnCr1CDWA3VgzL208PqCY4iCbpCOw3egItjTKofxMKnVEPMiaiELvZfEGmvH.2dgp61J13N2kzjDL3nQxYG2nzDYdbXM.GOkHsORIrhXLvhp1k0sirV5ExgMHtnamKk3QXs9Ih49XSAu.p2Mkl0VSW_8PQU.8m1yjaHDz3o8n2DAKNsJhWP2kDSif.BeQf8cYSlgrYIOJ3j.7dGeQhy5s.YfwvV8Hcruue34cQocXwQEpCTS6tpRjDqUJEd8pUytis9mPfsqHscsi0ur9XtfSZOfeY0NB.y9hdcmvOotuTW5H8uLvJOeppFihy2TZFfnn9E5JRvFpXKvk2gqC9HuxjMAqptkCU5MtoxbPOloDOpwuFN1N6a3weEz8mdaRwlETQdrPiOs0E8P.okC2H5yhEpxN9kawSD.baAbB1IX7XPj9t0xy2M3FcSRvPms.5eYEPtzSdNq8aePZqxwLDO74sFIwAv0w5D37f5qI8tyTLsoCFKy.ouFEzT8bHnmJWnHa_kTwUitE0JyI5uEiEZ1hQM2zT3T35KfWsJNLNa1bl2VOZQCtsVTvfKltY7y11GpXVaF_P21sycI8_5hJDMN6y9.Wl54C_wD437adYL2hvC2q5x.6zFanEz0twG4r48dGo3t8Dfq2qxN8IRjaHQoiEEtXhVLZjz88rC0tOuK6pkVQv3ocNTKG5cXoo9m212wqypJ73Hpd_no.zsArkA94gjOwKDusbw5v5cAJ7FA_n1kMMat2k2f_dD2ldCk.z7umEiQK7iYrDumRpsxzyeyQ6qAvlMM_5VrNhs7iDHzfvwt80N9XBkh1ZWqPthgnxZtkRHXroycIuc_2Q49Nx4xwyDsH9sQFGjrrlW0u401Bc8di4z6sU7LVkJiHyYmZOJvfQUIP.ztBjjhntl0hQWt2UgBfWq_aTyk7.MKhCqJ2E9JrWCxLo2N.Ogghyx9nvRQ3NryDVLuEBNM9vZv4F.8tVkDy5gw",mdrd: "DG95IipCZ6vLX43CD3E8ZNFO7fUrHrv.JdvMgB5GCW4-1744173315-1.2.1.1-g4Adumiq1094BWpix4Y.SUE_Uj_NN6NgnjF79ldhwsF_ioFiIgM6yMdLmcCWu8Em6ItcgRG2wVrtrhroL32Xo0MrmkqSdeTdT2CX3iJGF7ySv899xq1ExH8u8d.OdwS6UMMVIAla4Pwz0jzTAO2AlRxFeFt4dM2gBNo7qyOCk5mbFRkFkZaxo4UdC8MX853wjII1dPSD7wyfMMWRgx.IiWIsEyX2DFhsFreSJwPnt8fwvIDIE0kG1irkdscn1TwK.PqNH6ecVAwFdfyxMzipf2WEk8a8MuQ3u34NJPLhDbPC2zhwyTIvaOzqc5LAGAGk2EPSN.9znlPc6aIKjJF8lPYcdRj7bwmhfBH7iqZlg.7jRMvshUb4EkCsDa1CG5Ja9Q3q3MLlUpcS1g4cTDSTad7GCnQq6GqC2GFWEHst093VC8dmavMxys0Pv1bPmxsqkdOne1Mu5RuSn4_ZYh7Jwmnx6U_Gan5NNPcOBQt.ZRJ7prfGVcCJTbJh9OIzcSVzH6RLnb8rRd2n3XHlBLLOCTxe3diYK8uwNthJiXt1wG8aDspbPKqQC_MVyi8inA.spBgARu.Vnh97Bfn3i8qs0uqHcu858nvj0XY4dMUBlVsn2DEnHxqLC5K59_3vZ24RhRtSh6QRXSXniGX6yAWxZHhi6h4aHpCIxThCeW6gLxdRGHeFGZXYwy5PraN__0AN4JTO.eJ5OZB2vYCywpJ8xHvDKkvLloMk1rxnabFDixo9oO03P.38PpmE.MySakPU_Z7FH.Ii647oL5WZYUWJLzqYPwWNHKJvaC19NYKQyxqbXMWITmTGMRVwyrR81qIGKlDIAOKFwNGf8YSp5A43u1NAyY4NRQmpKWheH3EF.NdE.hC9eiKxcGw6fOI5TH4Yhy2sB.A5igKiMiJtOa4FTUafK4OhPh4Y19OtUctQlUJm_swTZmOVvMgINpji2kGSxLBrhBZWW6SfKSWk3MTUf1kl7eB6m9ZXpT38oWSWPWL4tBv0nMgpDpuXk3X_WKUi8tdjuOrSgXcNTOSueCPGsASv1RrfmqLebABBF1TzT4dq1qRORWZc1sAevgAYklsG9hoA7s1kEA_oxnIAKxCrRP0z6_MAHVFx3mV_D9zoq1VGetIv1deo9NzYi1prvOIO4A78TxeETWjqKZtCWiMqG78IFIGN9FsIIA0vX2WUhGGkYhKcjQSX4qY8K1Yv0qUS1yPKonbUQlk2pc93XYMIp1wn._QmdZ_NLZMAmiH1b.sWbiHdOjDZcAXDJIANjvm0BQ.qQiMcSLraNvxfddVm.FqEvkc9.KtwYnYpPQ_uC9_My.rymcMeZPdJg1vIQkH0NhRhU8DUYdIkORcr0.lISNgGVeWww6YosLjFfiNxTwNbec.E1ZdBuOQCmj12A2BDrJ5LRI3RDPrjmPMdxNJJ1igerUoljVawaHkWClqdRzWLZP7D75G_.kKpIwhpRr.zi4G.q3_3wJ6dleuIj1IevcPTjkyS0rd14MC7Otl7jcVmSBiShPh5HDnimWIj1EQbu3gox5Nm5f2dN_T5jElSyzm8VPNzAdmqh_Gcq6FhhjRk6jyBMAvNCFv6U7p6ftQF3JzYuZ6leF26eFmpuBoK03.LLlIf_o9NkZ3yt88iQzqAf5echZTKoWOTnJ0m50P0bt4fVOeuxmdIrFb7W4TitqE0UiedWS6A1TRYXfjCEYJS8e_Srzf6augRCtWS7H.y1rbvZ7t4CdP.vEGO5pp9Sh1Hj2mM.JUG_eBQBPtLkIS1QWVdut6DCFUJic0gMVI.3pVkcg6Kory._k0DFpEJwi6T.GS6NjNcT_UHdJa.9qeFHw00KXELLTRWQ9WSfdaiPMZHytrWRupKQKr2dOiGJyf0Cptri8b_GB99ackQffrB6Bb621CiroHWKX0oot9ZM7Vr.mhJW0YsNH2AvKhe05Hc1h3O1zow3CBWaEkHrDyBbkXEk7hRZkNml7thQZEM5qvgSCbcqVtZoQs0bmnHMSPKa1u7LQFdGjXZT4svBM5fAOoGOFNHqYDQ.nBvKICj"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d74bf3aeae5f7c';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, "\/1513.26076?__cf_chl_rt_tk=KgEHFZ4iqoS4WqEZpU2LhqHSOzBcfnfYZkAePTyPxuw-1744173315-1.0.1.1-l6QzR_EkENdM.BHwMwdN_6DM_fYgGc0CzmSsrW9JSXo" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>