CINXE.COM
Just a moment...
<!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: '92d5695c9dd4ce71',cH: 'Ydfdkic5rrAoKf1IRudBNh9.zwecWL_VNjfxuJ8ppgk-1744153548-1.2.1.1-67XsDEm91v9Co4FraPjixQj7VxXqMp0mmksDf1eTFubDdDvFtiEjoPS6RbfJVM6G',cUPMDTk: "\/?q=rf%3A6527549&__cf_chl_tk=HeB1erqDMNhtiBc1p0ypfDTmXYb3DQ05iPZVAkCFbCg-1744153548-1.0.1.1-nbAMMrSzSZeCJs5QwYJLCHtDA7OKU8rs6lh8h2LF_zI",cFPWv: 'g',cITimeS: '1744153548',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/?q=rf%3A6527549&__cf_chl_f_tk=HeB1erqDMNhtiBc1p0ypfDTmXYb3DQ05iPZVAkCFbCg-1744153548-1.0.1.1-nbAMMrSzSZeCJs5QwYJLCHtDA7OKU8rs6lh8h2LF_zI",md: "AHEuYgAMyvnDns5IwtY2QvT.BfPkSHZKJWnxjil8tpE-1744153548-1.2.1.1-GnhSqqdYb0ARWRcWoxV7sJnyJvs61P7sO4zTfVEdAiqJykPoKlj6Qd2.vUpcoacPbVkwcy294FzrISVFePLXDRB1p4UsGGOCaQ.8xcJH4L7QizXggyqjwJjNVH.KtVY2ETvPjy74sHpxP0qmN89WPu3T33M7YKVwAanutnl559TTHWUMmg2n_3HSCKsKIB4L.mWoY1e4qdq_zuyogBCLJATGP47hMTRm6DMiCmk5aVYneFrFGgzE_4nXQ3xRTdArDrV1xmQKgG8nZjlGyG1Elg0dGtYpCjju28SmAi6nd1dZ3SHfTv61jeFz1iIrnJkX1EDNFPlJljfFDj2imHKUWs9TkHPQQfgvEzCwHeEV4Vlf9LCLE1l7g3aV88zT_4Dre2XW_JWUm5zqV7pgBQFvoGmuPW_kmbT.nfHCTsfpSkxGf_Ag4qSUwVirIVE5gWVKq.CUkAwK93Z4lQBDzUSna9uMUz2vl6mGs4PIwCFcFTeBspasPOjf5ibnaw1g9zqKvDIh40E7QK670QJ3XTnRGBLu_qMbWxtggdhq0Ce0O7vX2ERM4rmMgKdmPDGLoMRQ7XuAx3cp36mG75.dmbeGu3FEGM_S54wXraLN_mG6TkJXxqz7gmoACi0T21DEhUU4U8U72IqOefFvzZbAITeHLvNinHZRDPnbVXODwQTMqTbeFc0fjth7fFzBA58HKqzn0ZdisTdOmFo0HCnix.KY.98v25_XH5HAWHmzoS71VME6I0TWPV3BtB_6ueuMpY839PlNddIQPT7dMDyL.TFosQtY6573sDDZ4Px4C7vsufoHDw4pMInOW429_3pD3wFgAV_AY5cAgOnKqIGBbTEw344lna_dEbWSfP9xTQCIR1kPFm7oTnlNmP5yPM2b.nEK5IGWB2cTvwbaFDWiQIuDMKxGUdgl2SpKTTyHtNYSlK.ObdwAU9gyTBBOte8_LTINMQ89SjI0Ycaf7iQszItDL1SOO91SNep0sK85DHZQbYA8G_HgE.BUcAMKQDRZVHMi2HxyB26jWCEWZ3gEbM2Y5FfcX5eqNnXGisg4i4aCTHrkCKdPwL0z3RePT4BBVR5bTvuhUSVLhN8reQ7AWCOvtJvKNx0dUjZiSWBjOdwvEkUMmVvPctih3zC7Hqy6tealqLIaEFhbhFIBzNsXqi_aF0Li6_n32e3w6wFN4X07MQpbYUlCAbA4UnrbyQ8bMzAq",mdrd: "Hv64yC.4sKRSv2VXZMMPVTGT2GBVgoCGEjQoqPHk5g4-1744153548-1.2.1.1-46k_UAM1so3ETj.7Fbn9LUrwh0XUtSxrAJFsQTerLthp5GiHh7LcD0ZqLQ6BK5zQpOCJq5CVP8CWLTdcFSyLTX8bU74Ww2DEpfcqVdVFP4ASvA_.O6zgQxISZ5dek0rZk_s8KoUBlW8UttjAVEZ3f5xrK4bHZAkVYkd_dFBFwYsYF0GWMFgdN4g0Co7i1W5kTo71zBIDWQjRALVLT9F7vMPtegOAIMX1VstD4jk76ZmXxt8OnNCRtBbANcdXN40qQquNacJT6fmDL0PfPo14lwndqt9WnXIqBVFg1cZ1s_SUtwS9xe4vRTdyXPzBQY0Y1_7RXy7L3DmGNKr1aUDqAe.TdmtHe0s0QhxBBmMdjt0xV4oRZODQGzyhahcArCoYCz3cT4cDAWWjslVTDrJl6q03nwZozYQm5yGS8aV73TI4TnMHgJecuywhl.LwvdjhRkYEvqS7ziGR0FukfoF2.X0CI4ARnl30x2g0U.YveSU9_H.Qc_7YdMyFb8wRjssfwSVn_XhKf4D7jMgscwoCroB8qzZhBtBegMNjsqbb4cHWg7OxjhVcCassyMUoAZ7c9TJjXWOrdDOL0LiPn3mtSmv8MLsU6.MfEpT4XJco2h_6acOuzVaGWPqH3hd0M3AyWAR.HnxWDUoj2pxGKKadYEa8Vq0dRhLtfKxbtmnZcRNVM5a92v6PB162L.iEzbTh4kBu8MpTJ8ureeZFqCwGA5exPlxbv5hHVTfaAy6mCtkbbIjsQQwKfJjrGrvcNUkG.Wy3OqUhNh42kJ5FgwJWQM3vLAUUPPM6tTJnAHXBxa2AMWaEEsgax_Z1BJ7U5qJ6rR87yU83wsla2.TqyLEvGZrmh1QylLWGRsOLguSEORGkdG8oQmJCIiZ5ziya1CTqtUgM40CTYbetdDyQPUY9JFpD.lrxEMCKP98bdyg.e.BisUsve5j725E9pDFmLI0vvRJyvEhXKoEnJRqBSwLAFylZ5DAEAwt0ZAl1NcIrsYF4WZqLZNCqIek59FRpwRXrDYWVz0w6EIAf684wu3ZqHS.6XfccDb9SxZ4H9IMt6y9b7q1rO_mvwCf8AhmafO3dUIXjXWLJZ.1A4yFxFNTiEdpv6PFTF8zLX7wI_gYnZFVDo18NDwFquc3OJ5cZQ1oNJafmv.cWWyZD9diBzuJYki_P8AAu6ur1k7ARm9UtzmSZ.U1ww4PmJduTnZpBbjdfxgQJCr3rlw.7eeGlzCSZwWLPyQYLWBuujDXoEhFFtoeFPpQ3RSMo_PggsTIDcJKOvXGDBzh26LI2W1lIw6SMGFL9ZMGW90EphIFDiJjKZBtEzzVm31Bhiiyj.A_jWc_opAtFTohv4Cz4cUEURx00BAaFRGnsxlNlEX5SMtOe513zpL2qCfPYXhZrmEoqNpIsJOn12Rc0PBiY65TqVkf.sKVcyb9QpR7lzfH2TBhL.jFqj0yHD1soRuOhd7.Vs5jaHL0Kh80rCC1lIDcmFIfVwTQpXnYxiofRRJUDpaxREpL2Fs5DxUvRWSC4UYXabLDOUT3JuICJvNMU_P4ZPzJzb5S8PDLQCcTuFBnKFJrJijOIz6mamvJBOi9kXeFbKsc_sVhq22_c3flacktqRP4UPFwPX1NvL6yiwGqswnXt3x3ka9mCjb91_ABwYpJB9heK6oQ4dy9.ZN1Kg38HO9grb03kUF3lqNfR3.3v9Td8IxYbGnViXYvN_NYXGCSpJokbl.dLHy9nzae0Fu5AacxcZIalvNLZzdpUaIioaYCZ8DcOMAt0l54QOZOe.Mjn9M3HcCFCt65CSVnj9NsyR0LgIo3zzDIlm4gfi30.LeozC96dWSEMqv7UWzQ1mQeDLfSBEJMYAKQJr_knfiSVwgY19wR.T7L19VDFATcZckOEIoE8mwZStrge4UmmcnZP4TjCpqkFFfJMJqOikZaYohUBql35ZvC5zrXCNfFTl9zoWZZVwcxZbbyQH2jjmyYV8hHLPXBfOMB51235Cqxs6aFnMgQzkfbM7d2aFfk0HwgQ79ZKKS9GuJ3DaAmyXSFSwb856ARuWIef.qmOtjTE1yynpQ"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d5695c9dd4ce71';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, "\/?q=rf%3A6527549&__cf_chl_rt_tk=HeB1erqDMNhtiBc1p0ypfDTmXYb3DQ05iPZVAkCFbCg-1744153548-1.0.1.1-nbAMMrSzSZeCJs5QwYJLCHtDA7OKU8rs6lh8h2LF_zI" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>