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: '92e16502a978f8e4',cH: 'L9zzd7jM4cddKFwC46AjZGsvpeCuLDz2o8Cx1C_Vdgo-1744279199-1.2.1.1-YNUMS.XMP.C6j9EIUNq7ybBp97UcAdvC4WPzyueAYz8uObUjgW1quBlUg3n15AyL',cUPMDTk: "\/1536.05183?__cf_chl_tk=XT7ePU0oByXL.AGU2qbowEWPtOkwho4Oyw8zi0s5qfY-1744279199-1.0.1.1-gXJVJFLXYt4a.fkim7CJ1sokTPKqUaS0bpLR97bGJDM",cFPWv: 'b',cITimeS: '1744279199',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1536.05183?__cf_chl_f_tk=XT7ePU0oByXL.AGU2qbowEWPtOkwho4Oyw8zi0s5qfY-1744279199-1.0.1.1-gXJVJFLXYt4a.fkim7CJ1sokTPKqUaS0bpLR97bGJDM",md: "xMgayYbyY.8U5qUZ0K93Ly9tMgbGGuQLSEeZLhRlwGA-1744279199-1.2.1.1-MJsDavz9pon_jAKaCTD6jPIzcp95HWY1430B0DHyFczgBqwefd9iQQRfC9BBoxRLVClzPSJEPKDAYot7dLt2KId173a2xNQmCFnEVG1qXeMPVe29rMH7oHBrXg8IugiBepBCpQEtWwc.K.gnSldFrSBjhUxuea2pKhfWIw3gl4zFNdvhx.85hieFUqfYbNZa2aSMO8489mKofuBY2nYFRyRhbM2EnXTa2OlStwTn44gi3vypfxxW04hT6mVT1yuYjyk5nxGAfoT2KJGqb5.ji_B2o46x0nyT18TOL9qSum5JydV44lXIp4ayd4SxG5Xw.czoTauv00HOO10NSn6zvsDFuhnPPXa7Ec4B25qV9r1Wf5OTr_rQQILm_sv9SjGJGqYQzrpIBxoOE6YPxtwSzthCqUWfRxjLvLWdC7.6gvvlat_s3R56FgJVD53gyA2l.lDpH2e9ytQAnZFRW5xPNPBgn8T1AZ6_Ww.0PGtSVm_nr3C6rN8OjgawpElMv9Ha.5wAfmzEKgsPuKzOhR7J3D5fFVNijvHANPxPCD.ZcEn30XQpIYj4YpnWogDbARkP_h2K3Lt90FDzNadENlWKTzt3wW4fIAwwduB5kFRfa4yCpspp1Cd0znm1hERy8uoEyh8nNKy6y9F5wpegU3GZAYM_M8W1bigPe79ypBIyjmGiFjFsN3POJpqvFgh1YfR58qJe5KI3nBpiLSr8NuN0PVQpvsBTTe5EXDlzFmmtx6pwhQw61xtZMjCY_2r6ZU2xQWiT5ggH6RhR3R_bL0U3XoL6Q_4i2xEJAkGW08wWdVob5WKi_O4cFyRPul.oaUZ2VA7ro51zO9lZvHYoJGovTgCjx14YhhN..oMa1p7BoXi06StUzr0quoQ1EdL4.ZQj7V8e7BIqTXwADRmGZsXASTdlt2Ee5m77oOv8lzpepxRedI53_iJZNzBf32aTjr_S8HHDNVUl5cEDLCz58VCJ78XruFnnWu5mDVK3xPL8A5TSPndo2_7HUH52G29FeFJ4U4rcH0ExRY6cR3CyqzisHhG9AG_62M4bTO93ER8I9fCoCkr.4XFspVlvUVjYatAOd6U3XC_3iNIWhajcbm879gWtrQrF.z4SqNEoUSL6Hq6Q95GTMlKDMeD17umWLAX8llqOb8yy5idJigFfZ1IlxLljsrPrm1huaX8_.JsXMHaG0g1.rg77oEcaxHedqj8e",mdrd: "bOP6IVofQUJv.8H1V5oRlmcuPFJ9yrqqLo5VFcLTzdo-1744279199-1.2.1.1-MU9WoImLfkfwwCv2OwI2T0f2vdU1mUGuY5QN7OCl2aBU7NQJyCvEn_6TnJwtJGxCRAvAevp90Nd0EkSBhV8cCwEdX.C1.otkqYaabnH6xIO0di7tTZPgI5lyn.SSKn_wHUOy2qeIyVn6G95TYXxlMWMSS7e88w97SMlO5yXd5WRung1sEwTHLh0YKgoVEGzAHI1ABcFkk7C11Rlx5nr70ec1lSTgPw3C0KBq6Y4NELft0ixzYYOm0PhisIUYXOSmc8Ms6ACiILmHGLZaaMZjKfCTiog5aQGYJAipuzO5UsoenUkel1lq1vHIjrcDzaFRxsuPPsrhDq5M.zrZ3.LfsSFY4DuCnfd2Sz8YY6VMAGnjGE6Ud4fabeNvSKVOnZctVHwX_qxO_282lQFNmqPK3VNwHP_WsKn6GmgQN_9xU4JqByEhyFGwnJo2fTmjvsdHjXok18qzhDPMofiOuGvUnG3_cYaK.FeggaBBWy4inrL_XPq3T.uhIl62vgb.T80eEjb1PSHG03IxVO25QlRw7qmHWz_FYFo6ITu_B7z7Wn5C36FX1_SOgJCrUxXXiOwo7r4No8ACbaiS5mt1_Ohqmp2Qzif__cusBje3_nIn3.ue9cvKMxwGcgWCTPMkLDao7oXT4fBNKEXpqo9AG4tX_h6MQeIfeZkveRPeAEVH5.iSucyB94bVWk6kA8kWUozORpjOZwnZNeqgkUdgRXCdvp5Db.T1m7eVXOpXplv8Tj0vvXaw7X0XDQ853LQ38IE7RKdyH7pmlFbLm_Xmar6MVJV0U1NsLb5sE44lR.7ksFnQ_hpZgLYSI_XwLZLYjVR9HGEFXh11wNHdNmlNWHykaQo62j3U.kZr7eANQ4nNBC74Zcuv2p3gpxhBjds4COJrTOUYD_JZz82x8Wrc0ydN4IZl1H.kRwuld9dnYa4vrp3kv4DU7Lwn40pCKSV6KrksxbDGlCBAzdvXDcynEMMvQLsT0wQ8rXOvutQKIrYtxgpcQ8FAUfn3dA7Nv.TSfXhZszVXh9CtOGu9F7xosxJfqfQBEI3HI4e1e7dltEjHOHLDNwKuFkdOzaqAx0X2yiECkXv7XisLk8mMlZlGDLMRgB19iLfeD19etsas1xPYhu4EBdImGqMrxor7bHPelHPsrtf8_q.7189PYZdIFoTA03FvuS75lNRjGP6852xam0VRuUm70sULgS_cD3yZSr8g5fodqvK5YIO73mVkJOWzid63czQebPvIovlyTG_MqL.0GmBA7A2U36F_zoRI4gL46CdnopEKAmj_Mzbjp1gsC5N2L17O19t6g0TxFsqsDlNgLKpv_D5aQxXSselVOCvEpAb7zhw5XgX24RrnOtak7mHB7bse9opouJZjnIEglr.BMu1K42M4ExYz0kAnm5AdE2HIm6vr75.GDjdM5OhRMsEZfxQHs6.iA4zDw.UHZqQsW2QzlWFcpHfMeN0Z6Zr.44dp.XeDul_jcR6LlM2PAZIXbytAhdMw_GEMh1dpZ4S.VkyKoaJjaNQ5W.v5PY057Sq6WVXSOL3qPSyNH2KT6SUkdefMjl5ysxIeaUY89oj0x7Jf27in8HWmWus9Yh0gUUz9pRYnL3z2_gvBY24jFjveOt0dOGuaqDoivuyC43pq2TZEg6KSdKV4jT2cGBAFGBKrzFN_LCfFYI2QGZtUbbFNDFZ7zmw.fuYbM0YMgxxrLwgPGAoIGQizYgVszwpVFfpO.KwfJk_zpjIm9ca3DXf_kRwe0JU_5UgRK4EpeV6s5H8w7n6ZJyR7n7uoO6zBSQAnstu8otTlQCMrQ0treQ7yP1r.BaxY_HykHwtmqx4sQ5.M6VHMX3hx6jnfIy0P0OeMoC6AnQWJGh4vn2g3PW9pZR1bQd9S5YylIWekSj2Wkqmx7NDYA5aC9bhRiodLYwsDaySBmWkUKssY7GyrV64u6Grzz65r2ghikpyvOoIzDeJ_zLcyCzDV71q2GKmHP3bYDNth_7Lk.2rL7JX50tEuq33RFXMsARaEtdWex0i6_WijvdWY_u4W5quHsl5NEe9t12uDaO1lIKYDlz_xxw"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92e16502a978f8e4';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, "\/1536.05183?__cf_chl_rt_tk=XT7ePU0oByXL.AGU2qbowEWPtOkwho4Oyw8zi0s5qfY-1744279199-1.0.1.1-gXJVJFLXYt4a.fkim7CJ1sokTPKqUaS0bpLR97bGJDM" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>