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: '92dcc198cbf5fda4',cH: 'ePVXeCjgPxQVgknCwqpyDPFsakQYS8aod_bDlIV1Flw-1744230562-1.2.1.1-7kJy3qW.Th4aClaW_DlDJNuRENgNu3fIPzvdhU.A_EbZE7P9er5tiiocwjGnqPjB',cUPMDTk: "\/1356.93056?__cf_chl_tk=HjvjylPSNJLV16nDXGANt2tKLkspH8Qp1LdoDoE.NEI-1744230562-1.0.1.1-vfwm4cw4_beb_5l.5iS.aDuyGibeMEigWSgN0rEl._I",cFPWv: 'b',cITimeS: '1744230562',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1356.93056?__cf_chl_f_tk=HjvjylPSNJLV16nDXGANt2tKLkspH8Qp1LdoDoE.NEI-1744230562-1.0.1.1-vfwm4cw4_beb_5l.5iS.aDuyGibeMEigWSgN0rEl._I",md: "LngN2NA8pKrZIKBx09xPARx_1KKD4HU26qmVo5gKGaQ-1744230562-1.2.1.1-SOTanrkhBVAg7Zvdw5MGsc7tUdOs8GfNKriC0ZCRYUHp_Bt02NFczbwYU06YN6uBb2umUfbIkXTQ4_Vz2dL4Kf_cMSRMJ34mftAg6k.D28B9VgObvEfHFHOPngVwzDhZ6U2yZRbTiNITEA3uxlo.ivFLfGqAH2Rhb1l_iQqmcHCrYsiKFiGoBiWeBVHxkjCWRbO6o7C_pgQRZhAiXzNj6qkAx_zQkiLoPGYEV47bRysjRmGGLiOgNMhIToeiEek0yLMOrmHjfscGlcFUnCG93a84RgxWuoa5xkBZecLGJQ8.tL.PHg_bmWX_U53P0syDGjccz2TVKIbTQaIjmPmIAgCYS15bu6Ms4WWA17iqbFQl.mhovPqFbQKxjI9cRNl0H0EF7prjxZwEBXj5rGF9rm5Z8oW8nWTUYAdusXfY3TelQNkLhwhjKDjlW2LJoOdAIGgVzz9vTwZ0R3ZMvb2LWOjy3K3KuKM9BvpbzNOwlr89NIgJOPeiYoMYZROz6vC.DHSNKD.Q63M2hgOqFd2UvVmIe5zUV_0XeLVAONq7x3ObaeRfAzVhsksbOdKJwSE40K_HaSZvNZfxJuVVzyTNvqBcvwUnrdBLejxqWquIS_IHSXBLfK7EkD1SMXuwTCVqRnzubb4ZKsFl1P6icitvTgBVlogf2ouS4YIs3TnFGCL8yjyyUaWQBHE2S8W.rjP0BJgUMwV8dlQxb8ex4EZtmMnMBTBXWutt34pq_yoTiZTQ9fCIJQJAiE86ZCxeAhbZzVc5HaBvClCJBElNjMoajf1NoIMYPqp3PGV4YPAiJzh3arzjZV2xtXH4Kf2F3PQIXUvu8lNH1bRS4_WD8H60z5w4jt7d6D.hgwZZHAkIzEwNml_fnQdvsKG.VpLN1UnYbWJQXBieQNasOzmmKRi2A36xq.SCz38WyOwhWEwxOyrIK7.Y0xi83Q4.9jZ.iMhfJpx6As4fR.idooyQYwwudTIyO3aBR5HWTvIfL6VZjP.iFNJj2I8ujQl5TXHTYvvzy8cdDXgJ_VgvxfdspYMZ8kHUEZBo2vauZGbGGpZXTHLwdTRyQOfx6RR1IoQhml594k2MLEt7Xctduj4Bgjd1n.tyLW4di8kmRtdJ8Dy9KxDjJTcKsGy9JmJhACUljPRBI1ouj3pVUJaqEDprWFROvF6bUyAhCoGUzS9ySl5os1o4NstXZifzfnpFcXCzQCEv",mdrd: "sJBxITEtA3s1lAYCQw1HVHuTDGTcNHqG24lxkQhkO9w-1744230562-1.2.1.1-WCtGZUgfVJ3rxmdBN81jwI7gHmz8Guyf27C5M7yb2JyRUMGFZwBi6JTQ4rWzDyPwcgyhTQnEb_unm9QWJfBgeAYQO5V_7fW0JsyH.ERgJvmqtkYvYDI7xBJINm_w5J39_qgQ_XPPf_PEOKyg4Nt3IoyXHDZQk5qrZwQcNiIsSv21W_BX0vjk9KQu0H3jHqgQzRUECwZ6zt3o2QbxTl2.scT9AHUFHtnOeomC59mFRJ8u.cmsGtpxXzB5Ykoc6.W6R3be6h3yTTqfGXOp5E6XZGTsGmNrfMEDFNnjPf5skDrkbtaaGO3rUuF0GSghAfFkjp3QN.DvVaZnyPOcmnkVGvyVNIWMbpB4dDJieH_GGemY2K88ah0Rx3cCmmFo4QtYj1tVFVdZE3_c9F43soMNJDMFSG1eekSj4YHc2iPBhO8Z2yB6yH98AP4zEQWkGIKazaoZQZ00V1mKelrGF8fQsNdszx0wv.iPDEn5CUSoBQ5uHApkGPOG5MjmvoQV19gseHcvv.ms2JC39hxE6vc_ikyOh2_n5jtmaf5pchUtwTXyhdXzPdxU.__qUeOnM2S.za.5BDz867_5vcQqq4OG_t0LBqwUq5DaNXWij1dUenUd2GY0od27nvYvjtBrY2.rYdITfkAeSl5tB_KwgJTieANz2E9gfC5vgqAnnlEBlYf3Q.d.nsVb9Nfblq9t_Cxm0N9iGhmuF.sL7KaxFmt.IqOTlQbGEhZCmsmXhCQQ.0SV_XgXnCNzgFRL.TzsMap_Ji4m0gXjl1RsJzOdvnbPel21USkI8ZLmC51KHj70jmtHlBTb3XYMuJpnVcrf5ah7kEx3vO7fk3Hqt3sY8.boTg3gvDozp6mFD23en.Op62Rj55MHgRgxaA5iGtRy.xRvyw5b4JoCj8J7_zMQeAIvjNX2a_JWbWBZpvX_LvY_jiiZ9oGVlGi5DD1yst3hAxBfspJ4oTvtCQh8DUn0r0pic5p64ULnlmqD5elr1KthlPGQkLv5JkzS4FcOnOSPbNavnREhYCdosdACh17s2C9yFgyfz70UmRMWwB_8MvqU1EMqVXvpbkfx5ZbNDVdk13MLFxGgl3LeFjpkKqOSMl9FQWMRl01n8sfgPiEsjmZlT2w3uzu7V5QFpI8NVDEcwMXu4Hz1qnd34x_8F2dEp1y7pOdO2TWcNeeHv7mln8LdLDWXOakRASQMBjLFSW28JfZuQT_DhET2IHCBqmQTn39wd4a2K1698RtSwB7sEJZ7t364.qz.iLbEUrPumSPuZAW9L8CClK73k9vJKWpa2sgIB5Qu2uxPWjZZk.eMnt.w45SIGwZXoUTGwbj_zzgugAFvTpdjRQg0t3B_c27uUdWqd.hEQMcQBdJgZIKVfz9m0q0R1xbVCGoCaBC8Wqki9mW_xSgGED0QF.IozYZJgpM6nfq1DZfOK_JuHy5ggsXbkpaq_CUJoqwEYinEoSVlt66ZGXPLB_lXUEVE3EkXusuu7FvIlMIZcQJrfqth1cX4i.BnvjMcMYCBzZxNVQQmuiosYIVtYavOl0ZrVRr1tN.1kBUaqMWLrlImDrLgXZSF0o0vvXmdkskCVuda9vKSxYP6iJ_w2pKqzLY1P6sHJurz9kE6UXoScvK.UcpHtBIRem2Am9WVhqDOnhKg5hoXhv7PnL6D6dlSo5z1t23Elu..uZiR_BoO6Tq7iAP8yZ9yU14FxQS4xPQDJY72GN55.cuTwoVLjJLsLkNF8dwfZp4BZ4Xwg82fIWrRB7MRp7f9ykNm86GS2vzgci1TrqeX0oJv9JIBpulGJVytffXZm7kfKaJox_w9EzLCFF0.VJvQliNo2ui0pFWUHwWCc_gypebS8Bt4U0prU5I8A7fygxahYGu8YBg22K26dUbYhAlRK4QhuJLOlenKqJFWhYmOGAPg7BR8FdBAtm_59WZFKUgAZm71_pn9zyAlCGMdkQasYeGKglTTV_Pwy_PLsnu2EMHt.DNCvltBmbvUskQQy9v6FFfXK0c__6DE6QgF6ecyKh6R2Gd5cpkq1qip7hKG6tyYMo.FCPQnbFZ2E62rgwU2pA"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92dcc198cbf5fda4';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, "\/1356.93056?__cf_chl_rt_tk=HjvjylPSNJLV16nDXGANt2tKLkspH8Qp1LdoDoE.NEI-1744230562-1.0.1.1-vfwm4cw4_beb_5l.5iS.aDuyGibeMEigWSgN0rEl._I" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>