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: '92dfa1bc9a0f3d87',cH: 'uLUKm4LjPeyGKPY2jMSLWtVTUk4IHi_w5Bgbu.CA454-1744260714-1.2.1.1-GLlJsWBx6RKzGUm31twVoL7pXuXzBcCGVxhlLD3x9ffLbYLH6pabU2XrdI6Tk6dA',cUPMDTk: "\/0797.90123?__cf_chl_tk=THvIzLjgnvUUlKCiiVqy5QHTctq2k3T4DpdYnlEm9dQ-1744260714-1.0.1.1-VaT6.ur5EdIMxu71EbiW1pi8ZzWeGK03wR9EQVpLOLQ",cFPWv: 'b',cITimeS: '1744260714',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/0797.90123?__cf_chl_f_tk=THvIzLjgnvUUlKCiiVqy5QHTctq2k3T4DpdYnlEm9dQ-1744260714-1.0.1.1-VaT6.ur5EdIMxu71EbiW1pi8ZzWeGK03wR9EQVpLOLQ",md: "jtavxjo8ir1dV8htp8fo5F2h5DaL1gDjsIt8f4OiB4k-1744260714-1.2.1.1-IJIeEBk.YoO8g0cwFTHqMrCEp3HYvm_qRKEKkTPMhKXzBunUt7KNItD5qyp0tWnbg8DtCSpEKebYt.mJ1FKA3EeQ3Fc0egsQJFOeoxShqRlnQWYuQz6MIv4nvEhGRmM69bIgZCKF8Ejp07_hm7Ndxw2hJJwN3D1TSqMs_KnsC._e90BLNp5kR5d0OwKn.RrgVL1RiS0LLxrR3HzD5xE5lLD4bYjNqRrT9c8vPkOJqRhS6pUrvpFv03hCGVLianQ8qFV3rr5GqqVIz2jZKaIh_pARn6QT3KBALvOs3WqVjQ_dzYYRG8o4LJRjmmrnHYKjQnbmb.USWA3A8d_qgPDZXUoW08IO_y9.5ndHNO3OLdnYEX3A9m5PyE5ZDSPFgqQjEck_xY7IFKY560yqpQGQgjneA8EFmn5_R_JV1jYan5_DlJpwytz8Ylz7L7QF7vk5_0gTCZwLVkgU4HfdcfhsKWCnr9p5N.VDMpgZaeFLNJWqqK7hupFIGhSSJmYm4D.yiJ508ZyHCoCvy24OgC0O6gK3ufEnpEwgScyjF.AVZ1.QpBvnT2CbAj5i9knCvfaeD3tr80GJ7STnnASOwGgSkTvHkAE52REZdNI8k3F04tvH7M_SPxU3c_4D8ae07n60bNa76sAD9z5hcVvBwiwaTxsBuIBtnT542qDz3MqweFiolrwmmLYJyYrqeyqf.kTswWnQUu218589SKo1ICIq1O0y71RXFwpiIpI_t67EwaVqFgl5HHBfWQUoi8pDmwFe0rETdpTnHScGFZb64H99RS.w60vXu26r7NIIPGl3whaffy3MpepirPds9xuRKGw7Xfn0R1jWt9QgVXtN_HfRTFNdK.IFeccaBtN19uGjQUb97wSBiYzeVoWkNKuG1bnuaHTsjWnGwYZxivYllsZd.DDV310_lH5shBYNUQH9ZSwrbl8l0f3YJmLu6yShWpzaMrFrVTLm62Mohq15BTtkUyd1pnDXKOGJoeMIjni4yJZGB_zXsQq9EvuM.YzXXTeKLjIrnd_qAXhOJT2Eqokk.sINT5_CMY9Mim0FQxQ9S0nQaiYsAjTeABstkMNE5lFGfnM4aHUOJlPCb135SH62idwRrf5F8C2WpF339nxbTv714ZLaTvugQRJjjajaa.W5Ngdafn2cMRG1CODjSdEflrHxcg9L5fW1tyLJwGGu2wP7BvhFH2hkhvJg0TxyHX1I",mdrd: "nJexAa9IA4qImNQUjwpNFbzIgc0Y_0WgIyUkZwAO4yA-1744260714-1.2.1.1-XSlcU3z.9CMBn2DJWZ26pCG0lm2MPfeFtgFw.kIElGIGolQ4baGh_o6dzABCBxqS0Wnftxb7hBWf4EL1AsjVABxRTl.WIYzdzpMywJtRQj0r8xBnYw8zI7oM5EX9zfupa635fJbOdKu1ekEIRx3kqxty3qpcGfipkwLuFQmnV9aINUE4Cgw.LI_yvr3rTQfRyFH0RHxB.VWm3DWmi00lGsOs7V9.xoD4d8kPGuCVlgZ.PMscTSI3YjTKXZP0D3jvxwnNoeVZdvc6nFuAMV_3gJqssitRk.mvOZoG0ddWAFz6ql7b6B7r4DG6nvuVvaK_mvmo_Ucvc12csEspJ0QJz.fTB_20OL_zEYkxvPN8I_3ppDrnoqxX0L0EiWlT_9dSyVuDRReLsOqNeX9WHkAhWIZSP8bhZRAnRso8KlNJux1Xj1g8zD3xqafcC0tqdt5bU61vCywV8RyfqQyiM9vhBK9A_W2z7Y.9HR3jsxW5jKWI12Z2Kk7sDfqIE4AF4gZLp.ClpnyoD5mzHAEsvPj2lPhLyICvCRKHdNVR2wHYrPOVukW1djGVNy5uFqncJ11AG.sljk51_S8zy.RA_t1x6BF_AVy6K.lfhJabKZKJBY32GlS_lAaH6cRcGuKq18AQvqs7qphwGpS4.SPjAxmhcEtw4MC9.pyz.Fs4uerdObb_UJ7gggjmFXnf00f1gPcZx.PB5BPtbwQkuiUAD_6TGj4ACqVNng4SpI7PXqZIHsSD3IS6Mx0cuacUNW8Y5VCwuSUrNVKE8uXnfRxVHwhrYTf5zfqI_2FwLDCVeUVq21n9Y.oCy1W.ZDTH.KyHlfddPsLpYwxgvDLJU3D1bIqM_gIbAGon_FJdQN047jONo0qsRC0i90cKfeaVj0m5SIYFCT92RD2AuQKsX2EAEThvyxNgqHzH5uiBJN0xjQjcCW1Lr3c1x.vxYDWTq9sqiBkf5auVqFPfxE6Ugmbw2qnUp_3740mRvEtWfXtKP_Xpnv0GWuPyFsfpziurzk8CL0aNiZkB.dwBdrx9BrPQXcFt5Ol_9Wu1_FqFp133RX4Iv_fSflPJU_nABzX5eAlSII22Uyv3IUliUGr2OgWCEVT0rFgojHfeT9CZc0PK4xFpbivCZyE25XAUUIK1uJFupexlL9_V7qlnWqtgxm2jP0u1AKVJJTLa3HrcE6UqM7Fq1GebCejEKDcN4BWSqVIWJ_gYY0qCbB6ITUXmxjMrVTQXWIMGuDNGIeuRSQvNaj2nWFgDUq5Zm69pi4zqFfY4k0VyHGW3bsaX63fl.qyV_4TsipWvTu5QB87XoLtrS8E_bpxPrjI6EPxnsNndfVxfRxruw_g9DTIqe5MjC3BRZ47Lg1vRirabv2GRK7ZgNy8jllI2VNcaAAFiKFMO5DbDwkl_O6kcQd2Y3QNzMdl8Y6rmgvbOkvsV5vcy8DPeCt6cNgWCb5LvypdAq7TXSCuaRggA6bxfIjMlS8zXNVHR1dZkyI.Vi7yj2e40UTXuX8RuzKCmauNpuQZUtrDthl9knfVFYJydQ3zYIT9Ey0rC7A.PKO8Y2G_ZlR3kbeZ75Egh4wztE1UniP74WRJZYjTHcsYDi.EuE0MykqS09VjHHV4QkCc_Ywlu5sZeRwle.CgrAzU0hOJbm9KgOBd1l314AcKz1Gljq40.s9lSJ_D1Zlv2H8Yf._SBvXnkhKccZUczIoDYwiDfhrZE1q0BZS_T.5bpDBxnLQAPIPgqRV5Xk5sKPj86C29lTmR4Uk0fUFSkyCOMhI5iymHV6upZPWUxcv69Axbxyekx8ssO0y_87TagAgo2L0MYIghRpyC7OXDA.qUalK5ezY7tVnx_3Vu.aIIf5v0UzAQSriJaQCRuV9iyADgWQ9QFtdftnUHkleF.e7Bx.fCCbl9foSFZ0eWjvRMP85fDwYaeUmEDuSlPvucfeG1qkEPVAcqIWWdFGbHcR2KFO1tI3qx4GAEUwwFQMPJ.wneMCy06recSlUmmscTiXBvrWdl5UGAh9nYQCrlwo2IuORNh6x10EhwIdWed.QPK"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92dfa1bc9a0f3d87';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, "\/0797.90123?__cf_chl_rt_tk=THvIzLjgnvUUlKCiiVqy5QHTctq2k3T4DpdYnlEm9dQ-1744260714-1.0.1.1-VaT6.ur5EdIMxu71EbiW1pi8ZzWeGK03wR9EQVpLOLQ" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>