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: '92d4baceacb6b251',cH: 'vlkai11tt4LSJjapMe1vclNqT3fA7DgYQqUXNc.isaY-1744146398-1.2.1.1-F9zPwLwx9pTlt4GEOc5zIt0IcXtx0rSaVaTyN9vKBWBWvoz3i6W868uqM5trMVu0',cUPMDTk: "\/0952.26006?__cf_chl_tk=c.Q2hWg1yFvPmvOKpvKwd19b3PJnvnuu0q.T4ah7j14-1744146398-1.0.1.1-0zjYV22j0Q5rjGOcjBvKxI8uCkAbw7ZxYHnkBn6nTaI",cFPWv: 'g',cITimeS: '1744146398',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/0952.26006?__cf_chl_f_tk=c.Q2hWg1yFvPmvOKpvKwd19b3PJnvnuu0q.T4ah7j14-1744146398-1.0.1.1-0zjYV22j0Q5rjGOcjBvKxI8uCkAbw7ZxYHnkBn6nTaI",md: "sgHPRXoSA5vjG3GrJE3LzaWBfTRgNuPEBVDzVikyBmc-1744146398-1.2.1.1-YffQz5c7_n9n03vy5kg8bYudTrBDjBIwV2tnl3WtqA5gt4olEO_DbcAtQyBP4G64dRaLpU1IF8mEq1lkju.gEKaSCRLCvktiQuVDd6Cly3Qll.aavovrrpU3TtMHc3vZPn59nATwNmqn6e_Szl3R_Nkl.PR5bwDuQHvRHSLXjoIkU7B7IK2duLKVKI.pIzRVrsgXIIy9dtyEKOsvqebcjJAU3RMqpRx0LXSh7Gy2iZeUdjk2msETAAAddOocER7nSp24i0zVAR10fgzxnTmLIQn1DIwhvO.9ROVlZ5XBGk83RI.f24Da2750SjMV0z.bSLpVIEvvgT3TGcw4lcN4ed7BPryn39vl10oj_YwP0SSgLQzLWLCkipCRye6U02lcQ66B1h_lsU0vt7OOPQMKd2kIFAjZHvTFIMAQTi4fqHKnCE23znuKkalWKPuorTDb2fs29wwUYvH8uwRtC5wJfsF1GGLZucFjODkSvCKWC.FXpeEOv6TvZS9Eo88rIBpAu9ts4iHn4jrPVfAYohsnoTfIj5SewkEW8cIQZNjiPS6sMh5jHr8kAxeQAAXL48L3Ca900HwVGDWvpXOw8l5BQ0Uh3Y4tXAMmofqv45FXcjRw_LCM.Z5hZUVFpJn2R_uOGt8S9xT7XpTaFYggWcRWK2j.NQ6vz56ICSViiTWobNo87WsIwmMzoofpnwFNQNFNusd2l42_ZgqyNv9OZzNtXxdTAQIuOLgO8Fh4enfjKHrJbkHBiqq.YLpY2283svnrfRHb87w5T6JX0IVxWlv4QD6lyA_ZnmwS61NOVpL9ADp2w0oY1Gfkfa.8iB33yCPpZH0WS21ZcbvFzkSZsUF1AGH7WwmzJLLO9xjFAtdo4_uGz4IFuT2.JGFky5YWbcT2NovC2RBhX_y6FNm4oqcYj_y3fzTRozShU_nw3Zr7Ky3fZpMW.pMnA.aqz.G9LpdZPTdGD8trFnl.tuCkjp.1ttmh2nu2gBUdy_9fXK.NCY2Ozqir00XdCC1zs5J6aTz5bMDf9TxOH6oQ8OM2lqe9ngpWvzle65HOdrQ1NdPCplIktlABLGV2q19ecCHf7aAUhNmBWKn70Y4V16dMZkiK7YABbQU1sxEpANoy.3B.8UFRpNJnAi2abVqNzHM412vNxTG5UDWUbMRXwC6kFQKRIQxMn1s4UmqPZymLaKUChAA85hiPUUCkjhYirx3v314_",mdrd: "0k1BbYylJ5eU45B0btjKWlqBRPu8zIaFuMbduRf1DYQ-1744146398-1.2.1.1-Lp4yTU.1..gK3ZPYUut9Iui7cFLyRJY5k0iKX14fCXTWFz3WKVdnYeYLYeEXbQBPY8M5Jq7HjjU7n66yDSHJZCKdgmQOzdxOZFQCfcHxYYsIg5pX3IYbvYJHZlMqFJ67f4ELDgVsIhi8RWp.OqjUjxldbceiU.6PofFr80Zq4wde8I5BgR4.6oDa0vaddalKS4aw3tuxwdZnciKZ1phCIFRMWwzFX8Jcpa1xDl_b1IHEbp6h9PB5en6dIaOQxy2lggNdlSAq3auH_r4Ad2qzAM1wNMOzJ6tV2EVDxerjQNeDmwmX.lGY6_8qjlYcCHFC5_nzOu55rCOpAZ6wqzMZeCUjc.SafL.ecThzh3rNSNf5A10TVQ_pcfOH7pajODH3mK_I9.xAdsYWcnvPxtrd3f8Z_hBUS4bI.gq.kUXYtTDzmc6odTBbtjTDPe51gT6La6bEQxtt9fFCofAhM.7NDiVnaxgEPr3UqAUCKAWDt6QeIv2A6tyBnNLKZ0KsKF1MTxu6VdWjEwlmEzbM5kLmZEYC0FCarDVdWlzDavpaRdLFXadqy04rB4zmByoU67phXspk4CL3fz1PXMbEuUFNOYRBIZXFCvgL6vFAjNm5CkZp1lCnvJcJpszFuf.Esx0fEKc3gcgVPcudRZpKjT9c_Kewx9QGVDrvx2FdA7sGEgPwczo6j.CcFaQTGPY.ky8i0i1RdQM1HMKf1rU6icusLDz.1BzOqdmatJpzp4mpceU0.FiTIY.5zE6fpLjOjtyIQ_LB1oTxVBs444.CEWMJ7r8YRRmesNs_rr0UMCAfjNHc.iKSUiKNkUMu0shHTugdrEKwik8uOVrwjs7ADP5Jf_73VS8oC4yDbPQwFgkoXvk9aWaxxOtatbU_iZW45LMEe2sj7ydc1yzgV_jgDXbTo32644cEE1AFBaopq4miuKAIZo5x8lL2eB973RzngTiQZsbYpqTXMB7OonMyANOCjSfTHO3CzTNkR13byyi.0IhjKYQPQ91Rc4PI5774GILi2Ds9ylhdWMPfGk3u1S_Frfs6ZqBMiumBFgTsqhTLpZWEfR.wvH9b3Vf3znGgdVGiWaS8.bU9xucQDq08ybFlU7PrVmQqUDc.DSp2sMfWbA1H71kydpw_1TXV3EIMqRe8OIi8WkD8BCOTPgHmNDd5KpgVJm8_n5u8CoqmAARLRrJOCI8_D599qHGuhmbQYtAqR4jqasH3a9zaSLLeat2r9Olyel83BlC7ZrosrBPyppzOw.4z.L6axsQCh2pcJpRAEW3_YeJe3kAkkqYBNc621X8SnqxTCNhm7rBfQ7.6hVxYT5N7q6E1UfpW.u_NtEgzriYM4HZ6typYXPIS4Xfm8OaS1nkZTSP3XT_8aU4RTc9kdzngFIZUBAZyWSGoT1qy5bUpOJ9i4DM75YtJB16q.8lT_gD.TQbP0jVrrqwiihLkjgsuOPv1Cyu_e0wHt1lLuIlChyloy4aHeGdSdbegL7sKcVUPRb34Rf5bzT1V8FMEoJ84.5WRXaNwb7wfvbNEyR97ml3.w4DJnDK56hD9IVu8z7FlwdsMNxPdblMMcMLJxxEMX.5OpVpfXi4oaiwo.xty7qozA20y1lqmpcoEQZUg4U8QYPvhqfrP2x0FobZTE79F2hrRkQqNabYwG8.vl6cikSLiHfA4RoWY0oJ6ZRtYoJN8hejoybgd93U3X8rCSQh9cKiXHS4GB7k8MneF5GfOHEdSsK329A2jLja3lVI6vLqYj_4i0q4BJbylNGI4ZZuoVgmhKESwVT3xf_GrJqeyMUvXMs4rjfN0Z0KchQ1xgY6iWiVopnqf8R5G92t4S4AVPD2WkDlWKdT7ca.fbtfK9Ep1Ha1gtgjJ8VfVvgCPr2tHZe0dapwgDVfbFZw6MhuUvW0.4d8VUuHQY9iYJHbyhVUU3XkRJIgm0FtO5UQs9tc4TpavQWSNrbq.p84PC3wJARk.xWoKHH.OxP_ZvoxnSBNIVqYTWd2Q.x7YgIqq4hQN0O_ApCeBLaL8q7Huq96q7Vx9RhBI6JuBbxmv"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d4baceacb6b251';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, "\/0952.26006?__cf_chl_rt_tk=c.Q2hWg1yFvPmvOKpvKwd19b3PJnvnuu0q.T4ah7j14-1744146398-1.0.1.1-0zjYV22j0Q5rjGOcjBvKxI8uCkAbw7ZxYHnkBn6nTaI" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>