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: '92ebfae7cc13ce0a',cH: 'hYBUhNWejTyhrMYwEeEzks83UI5GQaB8XRyxq8Ubg1g-1744390196-1.2.1.1-JX6s1gxfR.YR3.sLlhTY3RLydBTKMxujqElJwYRCaGlVGcEK1xzyYD8427qEGPpg',cUPMDTk: "\/0047.38301?__cf_chl_tk=iMCaFnF9OcPk8BRNSko6vELRkEL49q5vUGnu06GRLEk-1744390196-1.0.1.1-MC8rhS.a67mB2o8.WwGTDwst.EQmgjvxd76lNsyaNMo",cFPWv: 'b',cITimeS: '1744390196',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/0047.38301?__cf_chl_f_tk=iMCaFnF9OcPk8BRNSko6vELRkEL49q5vUGnu06GRLEk-1744390196-1.0.1.1-MC8rhS.a67mB2o8.WwGTDwst.EQmgjvxd76lNsyaNMo",md: "K51kcyqI5qiaRnqlIchcox9Z.lZPjm9b2cBoXtK6jLg-1744390196-1.2.1.1-Mfc1j3241hX8QIlICJ0cpCdgyUKwl6Pl8lws99mI5RToRvnqVKHvwU90Dg4GfZevC668pIgKeF153g_1AzRACyLmkPdWEummmSc2kSmSZTXdlmMGXLZ_OuDHiZ0OS5.lBoKTWC0UeJ_N9mY7g7sAiEOJ8pYawWdc8YRWEQQUlI0NXZydx5xB1dnzd69nvPxKheW_Ti_gOA.17bkQYIoN9yagXcpOekvm0kARYFAs.BPRBs8WL5FbsMJpzJ4uFYBO9Z_8i20MieaerP73HkrU8.LoZjKVDngjFqskCgbT4lSzMmJtIbYL_3u8HVpTOT8znsibkOTKLfpCULogb3jT2kGURLr8i.mKK9iQoVIaPf8WzxZnKzHDGWqsOlLM.EybqWomhTf7HVTVzItZ1NAC876wahTkv1DvA1PEcOvsWHa8mzAWR9y6I2kzoIhe.xPbwbbyQdUH2o3E0LlC1jHH1RV0M2PvpDPLGroBrjO1SlIfXpX76L.f7flRy6aFzqYGZNFPrc.qVacTmAX2Qw23pkQkmPJpS.RNmTMKKv_csAOE2gleezZpahv3GNJr_tb.EXAO8LBYwtJ5a7soeRqYFn.88qJJ2Km5VA5D3pFSJbaq9PD9KslUqdMzBqMyOga3JbRoTwbtSVUB2vkfAHwDb3MucTE1E51ms3sGujQHJQ7lQkzAu0ApJ6T0P4v8Z2u7E_irIX8s47PLL_Cw7bFEHlxF9SPDl0.BRV9VOo3jSC.B8GKTYoi4iND4jLzB8rEey0pADaV5wVf4khEK4KeTOJDA8tXrLK56C6y1leoQOrhba4nBlbANqNSQHx0JuKArFw9XLHaA4e4RN.wTSpUC28bMCGbg9tH7avAztDcWH2oXjE5H2q5djk1UDMsbaQmMyw_GZhqTuLGjPGKLPHf_aw3tFvIGktst8C6EK.mot1wy7mazHOII2mkbLUuQiei7WjxFAlI3ka2O306JCcxZxD63JJ6ndzOULxXMbCs3561vH5zkYo8yF5td4I1RyLxzjDJ5KIK0Vc2kYeD386HkEcqWhQbnRjd_oewwzUZZ8SirFtS8BBoBg4X_F_MFhcwrh5eWeTGo4H88GAcUysXxhzKybMgMx1DBeB.0AqmvIbx39VlqECPZhrH3bZ1EfCX.CNS6l3EqsDmQHQDSvFg2iOefVkZjA1U4Dsbv0_GmuiI18NnAuJx4ZwQFYFNkKSoG",mdrd: "twkaxvxnB93DYqWspL9RVidW65QvrfmOrEsdgL4RRgI-1744390196-1.2.1.1-1aYZ_9yp0SSuOukI_0CCRM1BrdbEOuTFesq2n1ySN7tj5MxbvndqznoMBYyHLvtAy3aDYB.TMDbJHTknbQRB1If2gAHfY8GnGHbSAkWqzaKprpViIekK4rdif2OhtuOH5oDyE0eK1e0qtL3jTQuUuUnz76yuPdrY4zwZd0ItmzL2AJEkBhByEQnVFHQ9ZzC2.qH8X2x6lgF4y3yQBltftlKQkoe_bY0.GBkbrEXB6AW6tPnYyVfAZjc66wTEpkJ52VAOFXwhyMR44gcA02KlgM5Uy8W2TDmbayPezNM33EjkAUaAn1Ik2oC3SYoDkc9Q2qBLSuqn2Ikw2zSbG5NU4XQYtLm3.NU2JKixvn3u3Aj1fd1rGOnTQPUlFYpeUhx0DP2WxA4KWdDsHEY.RxUafBipQlrRK4M3vgHUmuVWZGKlZGGpLm3AWPBJn5XKyHZwtGKrR.IM2z_06VSro0C4zZn1aDV5Fr3p3CsEmeflGRRfx_PkF2FVpwldFrz5MnI6njqyFCTAyaWq2PWce9ZJJOu_gqWhlLpWk8Ks6UKgWCyFXcIMdXz.fVAbstiG9jyi.pel.yKvOTvkIcwn9yRxFnWspx0TCfIo5m5pFg3imBayUT2.fgnuyDu0D7w.1bxRsnCDyuAruknMQdZL5TYauu01FeABetpNnPyu01_iP2dn7ISgJgLJGAqKFhCj8kKzhC10haleQM9WtE5oxVctLzBXlV7c5iLZBu9vMItX9ZYoq86WwwpaVqmPY9zBe6tAcr.XkryJd71zuUJFQbVAx6iZpQxTh8MfJ._Z022b6iqFBW0oJ57JPU4tE2uSCKycRb9L..7Ncf_v_0jzOybib5CgpaWJbgT1Zk3RKCd5sHj.034oFZieAN01Rc2JyfbucIsdHrd.4Qyrtq_xbc0KRcnsxaI_mwK1xl14oZ9o9Uf37lbpzBySP.spVIyz52d1BmMNN5nt5jDzbVYKeL8j0uYDr2xNHqGU7gOnEsx7S8ZWyj.qRLeKPtrB0z1.3vpG1OEWo0HQCXunZOLMBCI02XF1DcEk_0DrjH8f7T3d_JYap9th.KcWAMigqs362Gua9nLKizeYD752Ea.83JICBJSFP3c17ggVK.dIQGROCkpaqboEH2RU9JnurCE07jTk9do6O2O9fx1aGz8_GrfOExWeTzvuO78q_TBjBx0LscyEqwaq.2jOh1uWf6gyev4viEbNxH0T4B79HBircdge17H6nfK6IlbyGh3Kli_6_rgExXy7koMz._ErWAq.RR.T1KLmQ4MebBEUzV0ed_Eumqsl1SaMoerzjGvzGwlsXgsFELQ5sf4L8VV.TOt3NLvgDZuIPgo_nDdepdTGhtcYSYYjQxVh1SYrNS0gqEFv.A2X9pV4KfwNXMQfc0UP.kJmB2j3yceKe1x47uJI9lnxpe3VHknJ8D7dN7w85Re_JFFf4QSqgM.nGoX02T1n_RDhpTtKJJPGQR4FzYrNRuAeEf64Lf60KF6swCPjEihq0gKcmoeDisShkBQqeXWENaLLtKky4dq2pj8cZcyD7zh8TkPqPOx4V17vsuc4VxleqZhpWgu4txMf59iS6EmdxdOV4EKKYxpOa87cEteOAzQSWohlm2CeNFkBDp6VFFi_.bAiuyplEEC63z4Yv1v6u6icg0AbTbPAoHwkvt5YbTXkjm7EvVoO.ThXMy5Vhfle2dTtgJnI5MWG.pH4rCQGpbqOSflkUamkXRFKQzbf7XWv5Zsnf5K7XBc8Ps.Kev5mGc1Tedan6C5JR6rL9sIitXWIKSQAANPhs92WAPn.1nuNXEquXeyV92eT8j0ebqrYtSI_PVfRQt8dxetyyAH60lzbUR2sQjva9aOwqxQWd7jlAcrjHJCtPmeYZrxVxLUrDWK9FsWdp3qtwg2TLnsbcaEgCJAbloQQwp78zjaUSmiU7aLey3W0_qD_6oRL2G6n9Tj9KtnGCPi4dFIPXpNbW.2M3SRj0bzUmMGsUKD7TDqyirvGJ2Jk2w3u2oHVkWdt1xBwsFd319goPA_ipLncBRR52fzQ7w3OJS1014BipCQDUg"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92ebfae7cc13ce0a';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, "\/0047.38301?__cf_chl_rt_tk=iMCaFnF9OcPk8BRNSko6vELRkEL49q5vUGnu06GRLEk-1744390196-1.0.1.1-MC8rhS.a67mB2o8.WwGTDwst.EQmgjvxd76lNsyaNMo" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>