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: '92e50fc1287281bf',cH: 'HHa9GQG5uiEyimL5tjO_l325k5mnwDs0zCfOhu86.6k-1744317650-1.2.1.1-CMybo_gxn2.PTFhSZoFK25WO1bp__hv.xkSY7tKfbhfijNgRJewAmuCXudVfhOpe',cUPMDTk: "\/7964802?__cf_chl_tk=jc1wIPzUJ2Lv.GlyWitMV41sidTsXrAvR2QI9HLGc0A-1744317650-1.0.1.1-lVrfImiAsMd9V1mzKf_3JvYN7qxAiaQCqTKWP.wM9mI",cFPWv: 'b',cITimeS: '1744317650',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/7964802?__cf_chl_f_tk=jc1wIPzUJ2Lv.GlyWitMV41sidTsXrAvR2QI9HLGc0A-1744317650-1.0.1.1-lVrfImiAsMd9V1mzKf_3JvYN7qxAiaQCqTKWP.wM9mI",md: "8iVe9IOMcE.kGO8qG8mc.xeK.Oz3FBTjlOs_U0WYin4-1744317650-1.2.1.1-ZJ6rmaiHs3v9g0jLAcOdokwOjU2R_Mc4pkgsXdvYNzWywSYGCHaiZr5Vh9XQ87lystiwa_dtjI_3bF.63qWtxi1CPyvXJRNiKjlAaSM60Lm1qn1ZUyEwU.mqN4_w92s5TDKd79fQhVq4K5IXIUisbOT2QTTFVN.Jn1Wg.4OVlr6LZZuV1TywIweb6ISUQGQfMoEYTkKYE4KQQINOcsC7l4SBqCZf7axs.zSLV3YsVLomeQwmvfvy4Nrxo0AhB.oWibS00_GUQ7zCKigJ_m4ud2EP8Jx9S.4qXUf4m8eyFyU1iJw_uD6O.IP56NNYiBt5WEeSpXXzJplu1Z1_dIxjmVBhKtUVTbIB3lAUuILGo8Q4WuTzUYOuDuNGTzcGuQt0wkrQhZDrvrCaCD4MnBHaBvefGszG90gZP00ZiTeEbtWHhPgNYf1CPjD3gHBeIW1CEq67EhbsV3jTOIp8hNQSxRkgC8HSi2WeX5wbKl9rQ_j_KdDo8Auyy8eFmdJC4cUX5RvjnhfRJSDstRcITMgkzc7sX8eDdf0xJo2CCjDLjE_YqSC1_KRQcl67kNG0wp32tnUAU7tNGK05W4FY.etOx2XYGhdxM5Ys1pTHldmJp335PBcAgfQoRHmIyY9e2o9FIaIS3CAxwy9V7KV8QxGHako6pUC7XEwdLNwUaki4_YXSKiBnY1hceTWs9HL1h.gOwen6YyNoM8E9S3p4W0Aa5XPbttidLlVR02TL9krDlo1_eZQFlq2PukaW6hxDxWQIm7.QMpA5medcAw2optCSEM09L3u835fDgDcFD2uWBdXYk58z1IRC0_K0bhaDnx95y5kTUfUh2tu9PdhodsvbZ23WFfeRZsaWN1N6TIZ8tOo.vwUgijMz9XdQhS4AQwAutmHOYZVLllzCA1wC1l6whRRyGdP_0j2tZBLIzc144lJCD6WCSb6LuzcfRn1lnPRUXz4BJAazhTX.vGjzcCRJy2_zDj5.H3zUMe5dPiY7cDAjRL9KRzNnZlAf.nB6Sq2R7oAQMcy0_ifDjbxiofqxMaHt0XGLxpW8fbNxP5_W9Ltk_QNARbPqMX9YouynQUxODucFmzc0WMjww6yVU4UQE5wrK8XYDLfbx1uzXKSbKHZ7GBuHiyA6DHB_IfbNFMHNqWa9GVsYcHcfwZjfASXxyhZcCbinBxjeRwhPNaEwzK8",mdrd: "tskfUNY5dmLxIzWO2MfjvzciDAsKLyIvLpAwiCo3kTo-1744317650-1.2.1.1-hWYKx7LsjM0Cz3Ze65m612OYHOtdklkwHQLNAV3IXrz5YRtUlGst0K4wJewZux_G5xbMQbsysJTOr9gTJAPDYIMIwKhFXym31O6IP8baWs7xn9W3K4WSpU0v7uHKmIY2J0LNkaT..gcYOj6YRItc.A4hAwqODPMMVA1U1vmRiatauI3vLRqw30d3WgnmnE_igEFSE1fM1LmXgTp77tNixIteKwRre3fCDQDK2mRu6mC5hEwQiJt6D_OZzHUAmVKUXJyqJyykFTk1pRAjbz3Kkwvmoth4jTb1ImI1qv2KWc3MB8bak124pe6ga9VwgQ0wlwali9C_G_kjbXqMR7Cp7n84Jpd9mEJ78j4P_.Y10bbI2gKVa3oD4FTu5PXH4ZwGgps4YPz0mLeYZse4ga7EB2rgXIyRi2g8d5v2lI_KlJ8ZexiIYtg3WY30FPWeTCRzXxqBy3xy_XkDlrKCbpi9NQv6D0f9LL_G1ybjZErR14nUdxWgmrQqBu5417cl0gjBfjoC3Wn.2paeFWYKCMaeKJNntQvB1LOFd3CvcPOeEdRx_5w66voqQEAmVj5rWaNLJQoZQWpMdVv.9VgucIlRl2K1Bkx8k_UyNGiCwMGF1zinAI5_uuqIhWiRH9FEZ58PQRJ7JTleRG6in9mGsc020_J_z2VIsAt0c3NV8acvsgYF8ieQW1DYIgOnXJ5VP_WUcIVg0ClgIdb_4DYP6J_a3iyruhyjBraDvwEczLuOzv0j3svOD0YSZris0lUUNvlCcuKDuAaa0HpiYLqiFv.WzypDH17lliL9kyNaYtxGwy8pdfxDCPl2hAf1dovACGDTbixmwIbd884nzmFv5htL38ThkNJrEhlfe9dhMCTEqvGB0ypzczFH5s3TCacHtWCf1KFXrqJk45dt6kS0lEqMYg73U_mzw8YO8w.cxjXEb3YLbVGZ37PKP1I7jv.pH3ha_rAY4Ig5hbJn.TdeONQ9qngela_xBmzUHXVBhnr5q.OWUNqpuc7EEXZHQuwpz1ohlsWYt8n2TvhGPf1PFKIY4HpcpjfDBtnNzqfzlstRjKqE.08uCLZGBtIVmM7.Sjw5xvjBGZar9Hbqt6S9CnF369QB9PmCaG6fDTiXorBejoiKSU0WtcS4xG0tb7o9KhhgojmhA3O0aLVD3k4mNop0aJrh2igs0LhoM6jjKyAyXM_UkICe2SmnyvZgHfLlyhVqKqKEcdMA.lwUhqPj29ayLECRJVqVdee4sJQq_M5MnCtjpEbkTTer7GE1j1k1Zr0UDOtTzUD4q9MzDF98.Ijs2YHYeaCW6itGegnEg.2_sa1sWdZIZwUUCfwRH2sqH97poDF2AuiKp2ggJJO94GX5Vy1h.P85QZRq0PG9YXzJCNOhSAk8E7pDlEhNxEkr55BNAxFcpQYL71hoktjRVdPhZyMMvSigPxAu.zpV1wYiIXrPkkDrLWDa1ZFUUDFjIXwLNskaTs4gV.EX1s39HIu5Fm3K463utplq5RxUisixRQRCbXpbTbOv08BFSi2ddfIxm63Wkb9oM5WAwFsKCtVWz8UbK7PIxX6QzsVuO_jk0yvf.eaiuI5aEwORfVvC74Tz6qssEI6vYALwjvvjoBmoJydaseQPAYuOd6O5JeaPqJe5ltp92GX_HwiT.OGO3rqskHq96vwFUEw8PVMNNnH9XjKvvsJG8wlO6jAPNElTiIM73yL6QHWl2gOBUTbO9AFK_BMzAt6THOLoegYWUwxx9e_qPJqL15IvHyp0PL3ho6TwJxBaW_35JfManXDMLxnaoCfN2hDPkR0OmyV0HYUGvSHDnCWR4FIieXEEEUkDte05dE4hLhVQWYoe4jKvUSAHcpH19bxX9f2YcQONzBvmv_fFK_aCX4feiXD_UicBimGV7PTtQoJLtwfGiVW.Emk4TcvEqc5SeErzUuAf8grMUF6HX7QbLzCe9hu3GANeG9z1kC5.hZ8ppe2nWNh9D9q443mLK3ms1rumlBgX64zJa5RrTSjsP0jQnGwaOQXnQ_paiIZszO8B3ipy02kqmSGP"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92e50fc1287281bf';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, "\/7964802?__cf_chl_rt_tk=jc1wIPzUJ2Lv.GlyWitMV41sidTsXrAvR2QI9HLGc0A-1744317650-1.0.1.1-lVrfImiAsMd9V1mzKf_3JvYN7qxAiaQCqTKWP.wM9mI" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>