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: '92d3082028702ea4',cH: 'qFSQE9IjU_.Yx50zAHumnaL3UZQIA6AM0mQZc5LKV7I-1744128593-1.2.1.1-AIJiyLbBDBeCMWgfggKywtS7D.JjoPSawZIZihFYQvTE.vQUl3JgDJSFHeZedh8k',cUPMDTk: "\/0899.68106?__cf_chl_tk=G2LCuT10s28kjxPX.4fpcgVS4Wm0vjcfAn9cfL6uUyw-1744128593-1.0.1.1-.EPiF9WIu7iVwK_Mv8Zb_vf7Wgl.D.rCp2SfQ4eHXPg",cFPWv: 'g',cITimeS: '1744128593',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/0899.68106?__cf_chl_f_tk=G2LCuT10s28kjxPX.4fpcgVS4Wm0vjcfAn9cfL6uUyw-1744128593-1.0.1.1-.EPiF9WIu7iVwK_Mv8Zb_vf7Wgl.D.rCp2SfQ4eHXPg",md: "5TCGJ.SpM0BbYudnUnTGIpoIXqtOeInpuHOgfnDktQw-1744128593-1.2.1.1-l1mkcmQG7ksdevfBwn4S8zrVp2VJAQooS2HucCW6d7FMTxiyRoKl9U37gQ0kgMV3dGiwAjQqK1COf34i9BPChDkiNYkogrxzEevvrM_wbofdMOOawVgj__cs5Zd1gvJl5KhPTorxcNSM5cuW7wD7T9glCTtOfvXBcchHyyl5GrcDkFayHWpq2asjayP7D1D_i90c6tEN3JI4PDVEgjKxAD1JnptZRZpsY.lPWuycMi5MytmiS0txJty1CgKICzzuRIUURfPQAcuyE6gyAhnbdCb_0SIHzyhQzMrTiuskWh9hYYWRgEBP4kD.ITJWa74Hoe7BAWjnazWNl_prqTYJ8ChxlVVsT7hu6oFAOUlOowQFI6OCIyh4FBBvIrMYr1Krs.5jyPX8BCjNArbokit3Ln3ABa1_bq4JR.NJREkh9yqoxIF640tmaRyRfBjrZqiO1VtKHlXn1oo4xhEJU69Obe2HzEOhqKrBDT6FOj2itK0VeGMHI6yMpBnFCVrnSsMMJF0NovCCVbsZkfcSwCBloCVicLo3y6ObULXQnYQPVYQr.DNjLVfn_ysHwSi3hbPlAtavPaw1EFvQm3os25cc8mVtiF81smyon.BHIRj1tWBDfjZoHn6WpjrE0Gy78pRYLgZHziQC1cOJdpu1HPpWmbZL89Yegk9Me02.Ufg4p4C0qGqrrE1cPSqPbyB0.sMRY8wvY.XQ_3IXP9PNApcp2qRIsq3.D4vEUXsZHWOZCuRWx8DY1OzWrrvriYH2x.dNWp8z4t6OhGFOF35XH4sIUUfiaPP2aQZZQaGK1K0.aSA0lMcE80K_67QPuKNhzf_RCPB06QRtLQqyVcuda7c8d1hB0AzBUWQS_F24iIDBSNBqghwUpz1NjwiHPNRFUnH1xJJCs4zYf7j05VoRYoawsGq9khTg6j0y3K76LbqFZ4Jc6ycMlqSA822yzMFhMFK8osotqTG8IskdCOc_PKa0WtHuMJfkR98p6PAkbhntZ.M_8Ax19wVGkwiUGyJVKjMP7_MjGvqAkYCHdKdZd7rnm5iukjO8II.2uQPVlrOgUMo0pldTYgLW.Vp4u70d7zbPD34YLSnQJ_zgTCk1sR.aOMd9t0IpqKgyMIUA_7is.rCW9nwwIjR150_4.3irBhNM9wBDrDzPhTSmGTVnakbUFUPe.0gwtN8ff5iSvzGPTqLUjfm7L8oF2W8Bj1fLhV.r",mdrd: "7HvWQsZcTafmB7U_U5WHu8712VOAXc7RKNF0XVplGT8-1744128593-1.2.1.1-eD8g9j3TFxLux1dyGsXpBOmhRWUCCH.fCTmhxtrtizJKin1smEJ8.7ftHPgjmxkJmJS42bR9IB6qQn4aCJ_55CJ.AfD_q6Hb41yG0SvmrdalpOJf83oHf9Z_yWFEtdl_BLPj8jBSm0DyX4Km2Ayq9T5kgCNgYnI7lALYezG5TXQ7UK..Z7ce_hMGta.xLI0PfD3GXSfwPdAIbsbadLOoTJaZxbZpyJ0Cuzz_oNkvyz0IGb1Iv4Tm95s5XdKGM4iMgD0kaue.CG_BxJmPsVvMzW4alhw9ZX7QgmHO6Gg0UZRY6jx_vwGe7n7.rs7XxJpJIBswT6QnZ4fmvH6k0JgnuoT0xQX6UhCTPcYfcezW34tLn3UbI2w_bbcZZyfd56h.QHbPiGy_woC8Z8PCeAqqDOm7Fzthe8UD3qEMDeG_V9JIrkpXKSpLTpOid7LkfseHiD9I6oPrLBKx0RTMRby0nWFz01BuLRbgQ0jUVGxltfn1_7y522wMXpQCPBAYC_2wjDQRbpVl3P5ILWzSLBvQI9COHT9qiCGuAIyt4xo2BLUs.IgeB7btK_zsnDpIFLoiSQRlSnIPPmmtBpG5n41uy5qTeRyUR5harU4R8XnbzwKyoYsHabQSHSmmkXd1LuMFGP674jBdOARufGqTCdtNPr4h7zo.xrnmdFgmXXwiq1jdYIISr046mROjBBMTg_FIBLGN5Nb0naHS1r_FjEhhWclxKDTXJFWaIPPO.ShfJTBYfYPSDO.DtMs3_ZqRym3NiVX1ENFReqXExOhirz7vmOR8jBnPHwguQMqf1CAOEht9790IMa79brxc.k3qcTULfINvZKwV_JyJi286jIdZTvghzV7i4ByH9sAzFn_mvW43uFsQRjUer6zgseO9RPDu2Md96rq_.65oJGkBXBDsXxWs8SctqO2lulpk_HQb6HFMk9Q8mY63xdTE3xJBFu7pDfePEGF_f7rVd8hINCSs7vkpM.CWJVhFnob5oFk0oW8ov8DXagRz8dzlbEB4p35aWJE.5lvwmE4IVPcdcBZLxpr5jamjfmc6FkgpCSfbh7bbEzpzDDPJklhbxiJUS1a2CgJR5biEMo7emvwQpj_Zf5xlY4fpfgCM7iI7W9RkNO5Y6r0AMhCahs91gEa0LDp8tvl1PdKot9Wih10nqblCT1dGnJbiZEO1DmmGD4akhAoqIUiGWELeF0ZpXOTf0mgFe2z9hZ46xYVMlFL7oytvznKxBDRQ1S0wT1ek1kbD7Jm4sSIxb49g5rRyKFJtqAfZe5ccs6OqcucJs.2NVq37J.genCNCSJA1kbSiEgDqq2.A0r_JFvJxWzHyEklMbRliSJ7_tWBpsztUrrjTbHUiCTYqe_R92vj5wZEpx.N2vx_TD_h4WXOOZGP7m2F3DaRMEgdZCwJ2iiYpxiLvNLKdOFwUeoXB.3M9Y.ev9S4GTcaUuAS7F9R_tG_u9SCgmd_bEBQ4sgeI4AdqF6qHkbojHCClZNErz0Z6pV7CMqV_7veM98jlDQYJ3N0auExwllDcxQ5IoDGIr3g4M80B52cHTWPA..4_AiGrcRmUAyUaJbBCr1ov4jDr3geKRLvMzWdf7pWr0760dARDxdmWEYumU534UM8N4vXduGrLXQ.cACgudRaPlecIVhry3rdKkIonmnKDc6ZCZvb.8.SerGGm4YXq9KhbiUwq_wJg0KKPfwHunCjkrrh3Ylea7ZF_LnxS62UATxnOi9Kv18V2cSesThRveASr07AYGpBVn2WeadBfGG9WYoUSGR.EexHtG1l1jYrr4Nt.qTQvOVNpYElBGsV95Zz6QEHYwQXFLwpgJrc70Kh4jXzyKeluiL176YRyNRs2qFZ48rsxAMZ8viods6ckzh7_KSL08rfM473c8jyGp313bnEchlYaU3ZdZnB98UhnksZhnqlcW4V8eJItVEEMzFJJBgAG2HrDA5O.kWHBSCHzxiMqCHvZLqDs4_DSxL3UNLEDujyBDf9q00_sgf6PNofVmtAbbAdbiXnmQKNDEL_VQhi2clE4Iw3dkWvg"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d3082028702ea4';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, "\/0899.68106?__cf_chl_rt_tk=G2LCuT10s28kjxPX.4fpcgVS4Wm0vjcfAn9cfL6uUyw-1744128593-1.0.1.1-.EPiF9WIu7iVwK_Mv8Zb_vf7Wgl.D.rCp2SfQ4eHXPg" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>