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: '92eb2f6679bff8fe',cH: 'ACRcbXQl8TfohOm2pndS8G2JuJdcSf.q8pCY3T8LYe8-1744381860-1.2.1.1-xeijHRcL8WGSXyQN8S.dzECx0ZhecnZV3R0C9oTvhDjx_9offLRELTeviUM5BixT',cUPMDTk: "\/0666.65029?__cf_chl_tk=CTYjm9izoQ.vveDA5KBeZ9J8Zv1MimDPkFTiFp.bo0o-1744381860-1.0.1.1-JDpUb3PFVhuGWShMeqUdVuz61UiVcBpa72VsockJtDA",cFPWv: 'b',cITimeS: '1744381860',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/0666.65029?__cf_chl_f_tk=CTYjm9izoQ.vveDA5KBeZ9J8Zv1MimDPkFTiFp.bo0o-1744381860-1.0.1.1-JDpUb3PFVhuGWShMeqUdVuz61UiVcBpa72VsockJtDA",md: "ChatgijqqgAq7hmpLq1IHH5d8iHyv.xKtlxPe2lpBb8-1744381860-1.2.1.1-aQRMSgt56csa7QX3MEaDbLBqBIj2nNSx4rg6YqloZ1wxWT4_t.9OtnEnvlpQw_bZpq0pYo2cmmNErQmRQWn39Vf6asefuIC9.ZuBthEV3PuWZUumVWIgfX1vB2Domlf7BM_r0BOTLRISIv3PmFXR.KFBk.22lUDQ.rmC5L2SBnrULwoJKVCPgcYXQlu769psHNyyMbRjEKb.xfWscHykEyG6VuwqtzwD1ktmNG5t0m6KBMVOttW_CWKTuob15Qg6JjqKz5empZMN0kd11pVCcF_kXUC8uCwePTfWWAd8nruvgHlXqyBLncu1efBg955oMgWHp87gjuWYl7Dlg2dyfjBE5RoYHj7o28minUEBwpxD5YXN53zfm2vThUps1hKeKLRz_PASUulSoMA8nr3EzqiiEW8B47vXknj21jmqq5fu.b0TgshpJGchcjGtWbKpijQASaoOmztnIWYHCDUTMihbVqgUJdQ_w0xUcT0rwckxkgZbNXIY.lXX0IUdcwfr.pS0VA1_AsL_1ch7H_UwVzpqJ0ok6eVGF8UEmDDhtDFswlLXjSVq2cXwvyjq9JaxOrzsuyl.t85flIEDSMe8SZZOCClbpw9tEYwF0qakvGV8A3wDQN4wzz_2DOjRdWt.KH9gCKmIpYDugFzsR470jt_u3I_1CXttxqCfhnikGgmjbzoGUN1Asbydo1dQwwJQsPvIcJ6Pqn9.OxH.v4TbPNijN0OD.fCLHe6Y92kB9IrnEzjgiizD0VAIDRbdOzjr9rbpsQx.99RI6gGQ92SaU5GOga0eq.fSC1WrgdOuLg33CuQHH4yUYvLH4t2XfmixyUrbi78f9pZw8fLQYCNbFk5Ks_7eePjnn9JKr8xKt9FDj3xi1K3dTYMf._h0sBC06BMKr8oWN0zFw54OimCFjicenRiVOPx_FnU5uuQRnZ.Fn_8fjjUkyZUV2NdoB5N6mGYNMTXNHotqQk5c4yq_ofUzSq.S32Zndfs7ZxgEEdXZn4odmdDgUvWl8COXW0bYF3C3oIqCQszQ1OO2i.XCixMjYOer2ux4stSIh.FO5_KoTZxY3fjHrOF.prFO4H.QRpidoxjPAu_VqXIFMdPqfOlQ0Sh3w86daa3bQvZJCroKcdUmwzZ3q1CUHy2jbIMWxnG.uALJm7pe_TwH_flDWAzQh0GOR02W9ii2huMG.ePDSzn0yvT0wqwAGjaHydkk",mdrd: "EIHVM6404th_EK0_Qu1UMsWv5xJI0RvtYvheY5lmMq0-1744381860-1.2.1.1-9qBbnbZhFh2RiRUwMQlOV2jnxWwQM6YSX1sgdnU6oD0NSfmB8vn7Ipc1K5YnycWNehXHrnnrWSpMxTZY09xJDRhgsHHQgWKdGxSRvMOxp_Dr_W0iq8OOoE4l0tqHFbHHF2ZzWwVJiLX.yAmIxDq48OSA9G8e4GUGNWAnJSYjcsACUtz119561Pc_fJYe6XdbHZ.rm69uDI5SI9bK7LxCK61hj1y8nWD34g4z0gWKb21VYLwG9kjx4_eGFLW3RYprnmCWpMbT5iAizCVOBe3.XHL2e3eatQTwB__m2gw.Lg8i_AWa7OfRLnCLzqM5Quzogv3DEvl14J5dBYzm8nQxSYLIDSDiqF6LODhbwUPzlKPsAM5d3.xpIWp_wJIdwrNFi3K8G7ljtfhrrJmNrkMqUStGUu7Ey8hxP92mNUOJ7MjLC5aBFUgWQjsI7n3SfMSpULWHUReUH_ZCJD5eHWMdGXjFT8VME39y.PUIVCY5OFVrfrg2TD5XYb2pwlDopmU.0lD9AvJnIMge3mapx8ERFhxiW_IeMkNd7Xj4x.iMzQ.zp6UmCh4wGIU5BkjxcqOXi6A0mosbp93Tt.HLPK0XVyoz7yLwJbFEgttwWriYovtDKbjXCSByCQ0qwnlHsyNx2yu7g403XM_GJ.BN86XEHEyti7Cul74YnhhS.DjTP3svi_2_EaQQnhkXfPYKj4.B3MYFis.bUXzz4x8veWnQ.DjdGivd62iSHPZ7s7g10gAyXXgvaUZuAaW59FlT.PGuyELielmk2XexvWVXh6_e2EEKTdPRDZbgss6HySyXwh_HaNZqfrN1SPdgLgH33XZX_Jh1Dj4vLNBARLzPQaACIQKoFBvdSdLlv9s4yqTrC1dKPT4Z1iTM_AX0Do0qtusGAY4ftDUASqot4Eff5jeCMd1KpUDAuskX39Q1PVUZ91ZsFoye5wJHtIuHQKdaph5RRQkqLFFtH2mwLfh30AI62ew59Om6uEMiwx5rsIss39qi3.89gZhoa97xqPllEN1Cdy.2zQ3h14.V4TRcp0bw9aFPBrvv7jR8ibrUKWNaKaZP7YR834iSzGP9skNCced.SpCiIszRtbbcoM3OKBnpKNLyBAJEHlCyC8J0u0PReM7XZ78bOuSSZDcOdv3n2px1oEHAHIFvufAPAI9wYBeRmikkUnRpeR_qfr8DCsdNwISN8Ep.r.bkZVbVhxxtQVVPVs7jfUxVsq8vqPRlV_FnFm8SO6hmc3TLA3M3OhqOhjo7GXf5NRq.30ZM8ZbWR_JnFvksPSRp6TD9lEuIeIiU3U0za4643RYJ7_heluNObGF01UeSnJVz4xEusfb8LCaOqAreV1ZeXiDky8djUl.7RHd3Zejz3LLvpQennDN8XTRmq7tqb3YE0R91GR42MLncYgdpFgXN36cPLpVMjuF.YZSZ6gnGLSMqxQK_0d.DR3wa_c9hHIT1BJcBf8tJ7gVgmTpbo7e7iFxbB2LhCj6j0PNx4RowB1ZFjUYtlGAOJGZ02NyJMrKHi9_e3cItpoXBLvpaUAOvmnmaN6CAr3iXhF1dS31Z.S0Dj58p5w1jqAn2ZRGK25m8gzoP.JqQFrs.uY033FSKpb44_12RcVIYOIoChw.IKgnF8q4JIheuls6SAeN63CPtpk2kfPcCGGcFTBjXoV3p26h_wj6KNASCUMw509kodOkBdKaHpTUCwrm.URCl4wM91oFM65lPyEFxEcNkEqNTilhMESNHdfdLKop1SF0NYqdNmopk4EC8mcuKwRuqbk4n6XU.6KLbrqUBRX_zeSPlxSPtNUvTPlb645AqWMvLlgwgTOzm5DRcYZ1_U9BM9fTAOZLAt5xIqMZnLjhv70mhdISus5uxa97g9DlGraJ0E6IeQr03cZdTX5Y5PTTJhgM3oDCr9W_l2f0Mc6B8h48f2Y0cQdW9MpfMyYnBw1PbyqeHVJmE8M.AN.bEr.p0dnqi.lGVH_fBozF40IrEOoyOp_EUMh2IsOmwZALwMq_sBZ_mg2VwLqFk.Gt.zn1rvTYOQuw2TTZZBJV."};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92eb2f6679bff8fe';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, "\/0666.65029?__cf_chl_rt_tk=CTYjm9izoQ.vveDA5KBeZ9J8Zv1MimDPkFTiFp.bo0o-1744381860-1.0.1.1-JDpUb3PFVhuGWShMeqUdVuz61UiVcBpa72VsockJtDA" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>