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: '92ecdd2f6dfafe86',cH: 'Q7q7AZsjiUojd5H4RQNebna1XosF9qYbUnK0OaTBdBw-1744399464-1.2.1.1-YFex1oC.KNDFX8NIso5SCYvfQE4bVwc1GjrtNrayZjXcYtLwzi4wlTnW8.SAPKUd',cUPMDTk: "\/1153.93363?__cf_chl_tk=Fp5CSYe9diOqywZazQ4mmBGdvtUgchY01k9r8Y.MGM0-1744399464-1.0.1.1-T88C16kVrEYLUAgYcFyj6Nbi7S866uaNmfTgDuTkGgs",cFPWv: 'b',cITimeS: '1744399464',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1153.93363?__cf_chl_f_tk=Fp5CSYe9diOqywZazQ4mmBGdvtUgchY01k9r8Y.MGM0-1744399464-1.0.1.1-T88C16kVrEYLUAgYcFyj6Nbi7S866uaNmfTgDuTkGgs",md: "NDo6TFNLrLVXBfMyn0wtpGN_L0DaOxIXsgVmzP8KRvw-1744399464-1.2.1.1-rHNgu6gBYv4U7AuyjhtTTSQzIGWWaoYeCabVLIgiiiscw3wV.7jV2PKhQg8VOv9.GvdeXL7YQpp43rJcrG6c_xYVs1xA3hTjdNkagN1Py3yY12wS7csz_u303wLgbtVDpDIB954WJoI.J4QFsuOfqWH33HvvRA_zcPGARwjHwF7ntx0oTNnOqUoRHVIV5eVC1weMxJEBnzyTqSY7NAbp3ZASV82365HvwHIwCUfeg98esByQ9hEvYTRf0cqlQN8yymuf96CdTQuJpR1XMLyFJMbsaA6DHXZx1lmRuldi34A6fftP6m3jg67hilftlAr_lq42ygQ18twam47dJV5memp3zCtqA1waLMBwCAMt9hxUxH79P7dDqOABZWG0D9CbESkxulIApsifFX4vQccN.cgg2E7867OROmhiuO_tZXFgomGIVp7Ums0PcMoNfRc427ZWVnGxtMg1rk7_lsIaXSnJgYI0xS65Tgl4Z.WyH2kWaS_MS8m.vVYzrnhfs5AxHQ_puzWcQqaoUBgehczCix_TQHyfw9deFj5GloWNIzDs6liBAPjQJOFQS7NrLkudfEI4SgsHF4z5U_qgU0ohTFhhDO9MD9nh8tayibu9_QBk.x4vh9pAJqDA7.7h.e7oRzOl5hkFXteNRNB1ypH59XnU9ClShsMY5ythDYIGJxRmW2pHnHM6trr7GrJo2aFy_1cE2Ar7J6Fh6rB.NwTVvAQXIAFP0HWjfTpur4t4obiXsEv7PQGoDl3tKgqd.BvUqmGDg1u9wZEeWWZwcmBuRaxYOrTogh464oMd8Zt7bYR4WSoStCQkttp3nHx.w56snjO5KPbRyD.IwhfxNXyjqACbqhZq6.TxV8Qu0bER_KwAzprTgGlgQEAPqstLctSUfIQGzNU.Vfva_Ad_wlx2Ds_UNHaC1xGAzYBFCe4pUwWyGDMbhphtpaGrNcLBYQZrrHenaj88gXustC4WE9QoRsrCjXZTjA1ta0euUYpLiIAleKpmWRcJszWGbxVHO7npzmQGshMWcwEMhkCniNaOxy5Mkm25dEeDDilna4KFYYwOCk2wx._zz_YySK82BxDhsg1qrUarEKMRLvfJoNtqzYLcK7404f38DWlKh98Iw7gfSADKeCQT4mB1wlaTtuRwWYz8kblrlW1a98pvktDgx36yVNMTjcq4rBGWdo8AUMfol4YG9EqTWm9hMJZitWe.",mdrd: "WPMGW5P7hVXZWDAPS_VU60Vnmuk_przVahE6V_FWrgE-1744399464-1.2.1.1-7FbCMK8lkt36yc5SdwGrdSgooqyyglGEkdwFAoyYSUUHAgGgN7bVI6t02nq2rk_7A3O7h0vNNtYY0hNIP38vie0ji3ouAYGeb_MhFW07oBuYTyhr4zedIayw_08y4.Ilt6kVl0eHvYGEHhstsGeIykdr1LEmBlwUZgUi5_6eTGyuaKKheGPqfYF_W.2tFzz9JYwdNaDovWucmGZl5a0UQsnzhw5_GwCyPUolJ3FkTbGG2iB3ueDnB1YuB9d.Xf0uZcj..k7hX2hw0etIMfI7EVPDPCa913FIJGV9_k4cLRpSo5JChpmCBMbJpASw6MGrcdC5O9zXcIljsALECpd4W4KWiSy6uzHqUD8boAfUHen2k8Xw5KGgpcT5oGb24x5o3_UwjdgVqfSOIzyovb8Hq.5sIBCagXmZRGeSYBAWvMu5b5HxSwGdje8hIR7K0gWEsrNL6BEjMWw4UjmZj3nKRK_tOOHXyuA3HwYSQ9JKIPyp.rXDk6Eg3YUfwr4_C_KueNkWH8Z_pU_0BIEQrFNW6FYsH5zqpWFxQ8U8q.jwzG841bViq0_9v5VAnq3hbdBML8odq2ARCPOhzX2tauIqzSEudJjxUuMPcsi76PoL89c3OnI.qUrcVolsD9g0zUV.NiyNvMXMatg3jBl5tpEYhcNEGjTXabXcGBpqG_WiUBLrgLgrBva9bZfFOHczEeeM8rgGT6_7AUUogiATgSI08nytCz1HqeBI2ORAwGe3MT8t1NDseNTvlPSN2iQ.I.lcpxoW0hX4Ishuv4602.Uev0sfNAZVS7UcD51LE5QpmnbV3SnB1BIt9Kg2NKii6UjibTqg_adjwD.dhhX6cMUOy5I_iy_4CvsfJo6iGXnOHUyn7Ehfv5vvSLHR4H5.pB4II5pPajithWd5vsWkUMY2iftvmWJdDODpEHC0_mM4zFwFAl8SGgBPIhiUIXH1LUVbdb.XAvietWw6jGqhvF4Fvi1DMsS2gzbbZsZYxalyCBkYUwRdlciOvUCyDRMUc47P6Po4LmDpscfNleJY6.3yLhB885Hr3fuV.skOYVQo2TIECsO7zyJaLuBBZ0QklGN5QUsGkJKYA3lXD1gYxFPEBLa3jus5U.yTjOerI499Zd.fnMlF.LDvcdy5BSyISq.xzWv3orb3GdibY7p8Ual1HrWpUsr87ivX76ZhlGICslYPgV5_tTy2h6vq0dMt8ntst8q6RyZlIsMxWdUsG33a1A_M.z.cZAIGhXYKN.BF.uc8QLEgcwutqLlsaeMSHJzehZqy98_axA5o45Sl1PnIdutIoKV1ppLb9GQIb9ZTMvU0mTefQ_yDA2Bv86_4WBMeZSzkWAB5ywYmWD0ZV.6cz.bvz_zvyG.0qOhoiN_0PFt7ii.QTrFQY2JhneSoIQrNpi1x.Bie8UMYNgwHW7NiM2rE5Ef0Jz14MU_YTRwT2yivmtBb1vQEP9UfqNuf3LIspvr2jWzc_Tr19be27OVcLQ9T0o7ndKoCUAQ1lb5OQwgyk0.7_jtx0NkLCF2apF3NouI5F7mpvjwyddqjy925e4ZYBM4pml2CHiXnxb7GVbzTJ.EVaaGOVPwVwinX48D9uFE527HNhElja6uaueMZYIGUl1bGEq4U6bBq36EMZ_tkNHvc4V26U6oN33AjiCupvWaucaV7xzJ94Kk0CEvvxdu46DmAEvKhvp2sHZPz76B9SF4p9p482sYDk5gJtrRvIAreHLoo7fEppmyUkol5ArqP_vt_Kod2WA9lLxbdAl8iqJNnUFCsvSqxrFS6uKqtq8qja_vaVkp_kh_hulWAel1j7zLcpQgFpvTInMw27kUgBJ6jul6cihNeV0RcMrMGlVrKHZFtmpMVXcz9hd8fY2rEFyihWkKfPqx4bIoEwL5fmj1bWveFLNyinjp2ekoafO.JpX6FdqWMxQqgxHvAAB24L9ki2Bm_cgi2r_rbwyt_QUxxFyJziLh5og2jC.3UA8MlJQqLDxWUJ8TjYOX4GHZLIE2YTdc6c53SeugzD0GJOg1LPoVqWGvaKKGERP39.fm3LjcUfGoR1jrXybGOY0oU12t0iQB14nC9roxYFvA"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92ecdd2f6dfafe86';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, "\/1153.93363?__cf_chl_rt_tk=Fp5CSYe9diOqywZazQ4mmBGdvtUgchY01k9r8Y.MGM0-1744399464-1.0.1.1-T88C16kVrEYLUAgYcFyj6Nbi7S866uaNmfTgDuTkGgs" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>