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,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: '92eb7ee73b97f916',cH: 'QUrd.JSRFM_hdAWua5vykGMcut_LOglxonubTSF2jkE-1744385117-1.2.1.1-QEF8yyTwhzMJstV0kKpCFABKKTp2vzkgZNXDb_ux8dNBSzKdsx2j5Ez4ZTjJyFKk',cUPMDTk: "\/7785591?__cf_chl_tk=55SH.f7N7YX9uczw2A_T6Q.ZrHVtd3r9nvsBv7q_hdc-1744385117-1.0.1.1-2pVrIpYFvvNLuxN6MYho3FJh8GsF.FuII6Xj0AMkmlU",cFPWv: 'b',cITimeS: '1744385117',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/7785591?__cf_chl_f_tk=55SH.f7N7YX9uczw2A_T6Q.ZrHVtd3r9nvsBv7q_hdc-1744385117-1.0.1.1-2pVrIpYFvvNLuxN6MYho3FJh8GsF.FuII6Xj0AMkmlU",md: "11BC7LmTpUTe95kpbD0x18kmJoMciE475EOBZTG2s7g-1744385117-1.2.1.1-9dzJGjO.aBOneIbQPAyaQQJsQb2SvCXY1M5R3pNTJSP8lAslkvSDCBDmw9_Oo1iA9Y2Tlfdbfq.QUWe_q78WFh4G4QpyUADkx9o4gSLuXq0ohvT.kbAk8LFv3ZhmQa1ILHLpDdPdnt0tXivkq46SxsVmFOToGebPrqrPxkUFPS00Z8UUhjD0P20zYazFLHpqT93XC0nYqawqft8NvgBNrdbABfp_GAmknFKRUceWDgTC6RBclGHGtOkEQDsnetc4syor.BwikYPhRB2EqA.JzevFQzgOkBlEfzYnMkguWV9xb6OGtuY.z1G.dtwdswub0TzuyA8Q41wkNx7GeVPx7SP0Q9ONNiKwcV2vkecmcbTxyvrJr24DWxymyhN_HwU8md2azPCNgZL59V72Jsg05T7vVuXp0cMMfqXxBdGHpT7hnRpf0LocrIMEvbqcF5KOnm9..hxpvSPKipa6I_2ZUPc.kFoqGJCQxOkpw4fDHJWa1rZ4JPg1x9ZtaZ4ZjKNqEz1mJj8ypjvA5_yqpIvhrbumbvUUv4VnuIAqYscFVKbDpxNeXFncZLKR7UZuMv0WzScw5F78WqD7aVoxHC0KXJWubV0YbaAet.S6rqsLc7lq27z_Kjw1dqSjQYARmaJf9JqQSgyI2yZIEB7B7a9Hxjexqg9BVDDKeZBqm3U8XifDFW67nixPG3tlbyJnblT6rHi0S7p_AtKF9GDS.WW4HO7UZf5jXl_qPUmhEmWX5eo_nnJZEXYigDO59pJUh9E9vKM1S7SuYYelHfDWRGIiSLSSOixluSnfvbFX17frb9Y5kMbZPG9eLWjf86jRoZRhvV6l6Fn9MNYqVAUGn9KFhi4cbel68zVXBfRygnTikghTOcAD7kyD_zYEJdHviVM2AvLhGgq7a9_3Dzj0nu6v.sEMCfKD3Gv7JvwDgEfVKoL9.8SKy4i8OonU2tNgHWwPJcyfjHxqx9REsfKwGcgzFfg1wu4Hy_d7yLu9YFyaM94D_Hq0HG1Dpe0odlEGZgWww_dGPtv78reXYqle6GhKbzSZIDYeGI.CZDXCZLW_iN_1NNjy43e5hKEGJWjQqM1Ltf.Ca3WSAhsvhLiJCDEb.bXeMNfrTk.fRpGuBXVeeCqAZ1dqlUc5Bj.dtf_c5X7iviMM763kFiv303rI9ktUbbWFyg.l6KWgA84LhIjlMSA",mdrd: "N7i2Xe3QHxIVNIeIx50nKntDd0SX9Q0jQZKvFCCh8kM-1744385117-1.2.1.1-y.NP1MT143D9QVtrSv.cA.J5M.9PXOQBMGDUh6xXGna76G80AOz466xwS_Ju7w2sef2MWFUsGqpiS0O.cki0tozAA8SazfIcmzuPCj2CG5DGGkqX_OC9lvNEw4qzhQ4PZsuU.XgWd9uCN9krbdRZlWZ_o1H8OOvAbQRDjPAqD7t1drB1aeB5FQyvnhkK3CZ5mpLdTLQX9xKk9ey3bFDbTTXZmiiNnCN7CHz2Iy9H_ig2xwtK9kKPcj16jSxO0rpIqXkBisHoTe4vZcQxOTBYvKxcOBLk8SbO9G0_GZ5a00.BXlfyJ1YysJNybWMlJ8oQ5gf_8.3rbkZ6KVPJBQqQMGzFFu4uzd8kcmHBIAjVnoG4WWkAaSUKeLiNlSTxLMW77nMsmYilfYaGP_MUmCBXffjQQaKW2numX0vriuPcerIsuZgr.2hC9TAmCN2OLKpWQksmqDEBZretMZ_7tyPbPEcgZgTZF87jXzAveFK54pmJ1GweMg5lEJ_1126btNFJo0qrCiOSKK0p7ux2lUm4NXFB5tpd8KOHm1veMbR0S4HgJVp2Kl2hZdqrgZEyxRNo3Z08rq_zbww_5z4LN49LI2nTA1WWWakJ_Q.TIUfeclZDJoLVP9Em6Mx79V0rLDWlOi4IA2R59WxrVsVIL_470D5biesc0XjnOISzLMpgjsBPVSe.X7nhPCmak0u2iTs_Vv9V2MoXdylOa6RvYNIiHAnshmCeHloIIfSVv1aKgUq3fOmQPzqFHB992lx_KvuOS6KxOujRWVrg3WxTfcdH5orqWrF.OUQ5NgeGC3K9Q3mHPm2Y4eHP1stPaWgUJe7uj4SHxzdnr3.VV5N19d28fjLuVheJ5oYCB_sPTpnZXN.RLdGfI0ai72AhrLjvzQeMdC4wMiwDWSEkH_V4KLIhiUQ7fC2QVXasuSi9g7_k7_VUGjdZgPbNVRHzY.2j5bKPEoE6eM5sNl0GRBUVojMubTVh5_C6HOhFEr7usd0YVZBmu4ZDpk7QslYcbeS2wROtdctHFVDRYreJrEOO.jrCQb1xDbw_KnuiwIvfKpfWi0APjYf_H.OB14Fbs3zNKwjiMGFrNmi0gJRghmV0b4.QNwOCRlvvsdip1_iWUOdRY0hfc9.kg6XAt4UcZ1bTayjPIzNslAcQIGwCGo.IQt.ke3x0uBOHhtOBEtZqcxJxkxFGF7RqSVTIHNulUWx0UjnXQG3kiFQjFeoHIJVnY7W437C4N1QLjm6ueDHV6B_ngF.ASlEpZWg6VNeUoWoRe45RBS4KZ4GuY9T3H2F9ilzAwoSa3xhE.EcWjLY.jBqxQb17M_Q6SpcPGJGMwfswqcrc0_BIEaYsOxbHt8D4hsuHuSKB6QZmBoUMPNAGZsOBo9zavNEHQdlQd4w8Dt7v0Ows2BYJavYwIwEiUBgiHAvIRwEzCPYuNhYcIGtgWSSW1f9FAPSh__yEOZq98iLIeLFP6rhsw4pWQm28ult382GnmIaiDwzCAscR.Twl9nZxpaBJctcem01HzQH5lFYSCHOjoeE6SdkkxLvfXXpSzV6ySpy.285RvyTOYD.f7GFeXS1OMUWRP4t.XB8rk5deFBUjAAJ5_zLXSHf3cX._ycHBhXMespZuG72TlptquTTOvDTRfxbZd.yDnqwTtar0DDE..HZOeOisZNN8Ve2j3Fza59hI8Q0W4ZUDz50CsSx3Rz9TIHASYHuWB5YuFJU28kDWI1TuPWxFpWzuHX2dbVjECUnmpv2HliFfWqp1cxHEybS5Yvec.EFtEp1C8N8TbxrrT7FHMzhH6nEFv2XqeWNOsj_hDFo8oFNzrp1qSsWQCcJTCWgnV_XGxPAGhNci.5wvChzUXLlharQZj3X6XPfXdfW6mC1fvXsq7SZApXF.K7m5T4EAgXjVKqm2XYewgpWDRwhn41uwRIPPB4U1HxJxo8lwxEMbSOs8KFtUXnynKmeJtn9dJ2L8HKpJzzHX9.YOk9LlTf2Jwm866iCc1bvjHfUiJmFgeXSWGWhiUa8hag.ZfIE0s1q5_GBkZSGNAEqO"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92eb7ee73b97f916';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, "\/7785591?__cf_chl_rt_tk=55SH.f7N7YX9uczw2A_T6Q.ZrHVtd3r9nvsBv7q_hdc-1744385117-1.0.1.1-2pVrIpYFvvNLuxN6MYho3FJh8GsF.FuII6Xj0AMkmlU" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>