CINXE.COM
Just a moment...
<!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,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSIzMiIgaGVpZ2h0PSIzMiIgZmlsbD0ibm9uZSI+PHBhdGggZmlsbD0iI0IyMEYwMyIgZD0iTTE2IDNhMTMgMTMgMCAxIDAgMTMgMTNBMTMuMDE1IDEzLjAxNSAwIDAgMCAxNiAzbTAgMjRhMTEgMTEgMCAxIDEgMTEtMTEgMTEuMDEgMTEuMDEgMCAwIDEtMTEgMTEiLz48cGF0aCBmaWxsPSIjQjIwRjAzIiBkPSJNMTcuMDM4IDE4LjYxNUgxNC44N0wxNC41NjMgOS41aDIuNzgzem0tMS4wODQgMS40MjdxLjY2IDAgMS4wNTcuMzg4LjQwNy4zODkuNDA3Ljk5NCAwIC41OTYtLjQwNy45ODQtLjM5Ny4zOS0xLjA1Ny4zODktLjY1IDAtMS4wNTYtLjM4OS0uMzk4LS4zODktLjM5OC0uOTg0IDAtLjU5Ny4zOTgtLjk4NS40MDYtLjM5NyAxLjA1Ni0uMzk3Ii8+PC9zdmc+);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: '92dcbee88db7a078',cH: '0AGfzCBE3LJt028KpbqDlNiBvZfDXeY1c7U50SQ8YHs-1744230452-1.2.1.1-ZaxI0QDil1JLembM5TaD9tsodJqXyDwayM7aarVCVgECTP1iWrBviN3.ei4mYgMD',cUPMDTk: "\/1511.94009?__cf_chl_tk=v6o0tOV9mf84O6ZAYIClVWrev7Y8gUp3UwYMjFLX3ds-1744230452-1.0.1.1-qreexbipQF_vyZAyi_UylUQsZBQB5nG465TH.bUOPRc",cFPWv: 'b',cITimeS: '1744230452',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1511.94009?__cf_chl_f_tk=v6o0tOV9mf84O6ZAYIClVWrev7Y8gUp3UwYMjFLX3ds-1744230452-1.0.1.1-qreexbipQF_vyZAyi_UylUQsZBQB5nG465TH.bUOPRc",md: "oSXpNfhRU7P4c7udWBsb8K7mA7WQIJUW2ovgRdoRME4-1744230452-1.2.1.1-8sT.DYekxl32tGawEmJuHiZ8ptbZJYGuUdWYZ16kly18BgNXYed61WgHMkWNw1QXTbKcjIvI8.SrHkUDPhBk4RUB5VH_xUrR2pYPZGJIK1jD6SxCcdMbg3kVVFrYG4Dohq0CDibjEi3_89LYUgXV_g9MJ2fE3FxIhwjG9WCyWKa2xopuMyGeJhMXjjsHTrLGDJg.VEkVXWXGt6gk7hQNokztDO9oD.cLXGm1kO7XnAt2JjPIzYflqf.ZP61sV5cWkxWqrCs3dJPFeBCpZ4wbRHpv_zJOZFDT2jNX9AYESYN8Q7gySSVCjg8Btom429fXiZWr85w2Zr_WPsfkw0Dv.l1BOLE0TxG1vFb0FhFhlxnEKRVNM.YKL1wgp6Ungymh.AgTz7M2TtV3BEpHhnhlDBEyNVZQLexPHk7i4BA_j3BJyXaK_wSuNNA8J_TTVERMDkaqKm0S1hWYpKjPZtHEZcfLfP0mod1r6SHCDwa3GLagxpo7v533hsFdbUu9vFlHNwiSuUImIPUZPxVGdjs75R4Wvn0KOhsMFiApE_rHqAcnvJGCZfoeO5rxd.PnyE_wmcvC6rMj3hjGNOR.XJvXZqFucQTQ_Hb_lml.t0CzksqbO.0fWPYaX9TkqUmR40.zA9a_Vyg88jct_RMz7pre.GvajioW7jSBJxWZdjpHVLt01n.HtWIRsxamDMUZJIUiB6aUIdvyzYZszGZ8UZTUhxyxoJVn05HtHqGDTBgZszV1.4R6aUXHmv39.RY8.5rew4n9UKtIx35s8_hwGhFmWFpuDJgtegrikt.pRXoR7B0M7TEKWopsqaQDUK1uWlHuUG6VS3lQZ_TslAkn6x2uyKgnmeV9CnX8gXH7tmFOvBlKu2a3qQGZWVVDVtdOF5MtPSR1ZqqzbvfS1sBqKYNWRDEOO4oFrlvpTPDcj09R6QOTLSYjas9cYxL.QENn93WUqbckd6Ad0iB.xEzSNEdBClH64T0q3xVYkkts3hgbWO_qa2k9gfjEuuVQZVxJx6VyhsD44g0xDU1sgN4LgJTHBGZsmJ5ZIdnUj.eaTyQa51chl0LGSV5RzypFnBeglFEfttg7TrMNnTp3ttfffCF4plyn2FZ40IlsU0RMvLJAmGh.qEmbxT1aOHA8QjpFMCqUO_PMMzJv9_jhFGzStkLc66vA4PL.rRi7M9Zl5NTwZia_vpUl_oI1rnHrRbz90s7r",mdrd: "sqrk9bypZhHKAlIrF3qw.7GRHReK7ZIPd2AAZawup7Q-1744230452-1.2.1.1-qUVVqdWngLQDqqXDXn9fJKWDAgGZC2dnYmEXd5IU1byDRtBsGxsXh4CZdjEHaD1EpgAKTG02eyiB.KKqakGJooqL2wTmwQjmUFx8A7WSTWUa.PI0SSg7ipN_mHSgZiYQp3EPy8z2p7ioJk4RtKNSwcTVFJ6D2NGenQT9sVkpHiyRQ711Z5Lfeygx3RDKO2vAwH9H6MCgFyoTfLy9osa5k.t130CuGui5KNRxUoT9530JpC4MYqACcymWDSvBZWKpAEYOUtksZ0CA9c3QWaO3mhk7XLkiXyfQsp5ua3g24THhNGO27mFshWTOaFmSdu6o6O7gDrSH8LcMyQBdZdCtRk8UDckD5NTOKehbxY7slLbRldxFLBb5pP6IM_3.mDeVXxBwVm4lOiLCOz_WdT5XS7DlZI5jKNSYktxWgJ2NTyF_W2tknP.Lx5sUW7Ayu4LjQpP4GvCP2PKqH3tWj8HcnHIPZ2lpuP65Z4ZtXogsWV6t7jE8V8_gHjK8wg0.3_hLvm6cnAeLCJpoi_R56Tni8ZGfyfOo.X8dGqE0f8p4dH6pKI5HlLjTdl_OC_9JmvwwB3T20qPr4WrZMWi.koW0IvPgDRErpp7F9g1zKR_yaVX8OErdk7ZAqw.Wi1_Jr880rZbxm0FrnvswS5DQpjpr2CQ.KB1Yjb7ui0DkRL7PL7hcdwz8dfkb2kC34ig1BMGyg93aMG1MYji37RQXeoYrTZTYE4cveD7kYFAW188I0m.0Zi7q2s7XTg9w10RWlZvYaDRcu.H0NC1sroEUkd_XzWkNMgyXBbk_pdK5hZKBo7iOH6izW9UWss.DkdJPc5u6YJIW2uGA.JXTonNHrUJL1q9cyMdN_NxP_ErjcS_vcQzlvmleaR.JHqVcGPM43W_zCcoTyppqYjN12Y7aSxFGeaZLL27ePtuyqeXX8kdl3V4Gt.fhv4NdY6pKMomntypDuOLb2akB84YoOvmPKg3o1VAi69i_oplGwQD8n2i3H5sQZ7DGk0xDB9xvLAJWV5wMak0LuC_JifQx7I8VWa2lHI8yt1J0EmiSxJRu36qhXLJQT3PRRgEvGONUaPf7iUXTfgo9YxAr2018ZlebpSS8IwyBHw9yEg7kyHZEMyERxm5ERM7b0EV.i_Ip1Pj0QYfjj7P4IgS_Kt5KhdhFKavkNMvkKYpn3dfFwl5Ls.YrA.S8KhlFmwz7B5DKVcKO5FJtfdp_ZBy4OgQK.b14JEBZIQ_QnZ7qTaKLkGPnkhmDNRwb71tk8iVFxzC.G_RhJMyl.kqLaatcL.y83C1YJ9spxyUAcSGCy6vSf1jGE9kBo4kFoAZnKQgZVQUic6JiuGnffGPa_aMLpIBeUDwO.5bxUfdC9Iv6g8KEkxa2BVsJbHfoTT.XHWIgSPbCY4tA56.8apmxlrwWNpsofsxWpakmvgZh9qKTcXiuHzos9xVI8OLas..ifxGoIt.vzbdBpKIB7gISsNhwcMqRnYd0o8w9qNlDqTqvE.CHV.dVA3CGkVNFnGtgwNDjoeEjcaQDwPSGUAw_zqqPxcJCVpB1vZ6BIBT8eFc6Sq4bwzU2g0R_fHgIBhlATTek9oTOLLgRJocjJMHo.ZEa10hUjOGL1o2eaSIaT2TN6j2vaBQ14tAR26BM.oWyQAAaRt5nMjo8nmXPKdOhsSDqb0jC7i8gumCCBLTUFd04T6tvVBAvDj8oxXGp1e4lmB2pMoNSlcwt4JduGpJaQMIJ02K8vpcr7oBg7sB4sGxAdNU6L4hg3VAKWFUezfecq_bdsSz7of69eODVHGp.W_4wlAQiM1_RVxoWb59dCSyPIkssrEj.HjV2REEipjMBc_TKcwuyjh2itacyqxdL3oiCuseUVpAa85V7RPsTz7QTFrQYWs76beYGfNbQXel0MlVPxMKdS3smpSyS6TGxK0tDSkLlGf4GObG6ZlPNOkj3CtzewHzItUtxkrd.WrCqybhvJFEx_W4Kh9h6cW5IQZlnormS5HirOfwKBpOFD5gxCbVvWw3lqrm_3AMdaeVowo2YVBEfPO.LxvVh"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92dcbee88db7a078';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, "\/1511.94009?__cf_chl_rt_tk=v6o0tOV9mf84O6ZAYIClVWrev7Y8gUp3UwYMjFLX3ds-1744230452-1.0.1.1-qreexbipQF_vyZAyi_UylUQsZBQB5nG465TH.bUOPRc" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>