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: '92e2fe7e7b8d40b0',cH: 'LRVUgbf3yu5xxpN5Yp69hsGeihvrrVkL5QLVZ9Hr.oY-1744295971-1.2.1.1-CEh4SmcB_wTgaV3UnVCO4a8UEFaha_47s3G8ldMA3IE9cUGesxU.sSH6kLRM7wN4',cUPMDTk: "\/1416.62134?__cf_chl_tk=ajGjtn8SnlppGwXSwZtGKvXTQDshTMMAJpVaa8xOFog-1744295971-1.0.1.1-xTyjUnQ8.pLt7SEt1or0ThRIPiydi1C6TVH40hh19Xo",cFPWv: 'b',cITimeS: '1744295971',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1416.62134?__cf_chl_f_tk=ajGjtn8SnlppGwXSwZtGKvXTQDshTMMAJpVaa8xOFog-1744295971-1.0.1.1-xTyjUnQ8.pLt7SEt1or0ThRIPiydi1C6TVH40hh19Xo",md: "vpm2AmeHh3_G2wJckQOnq4gIMUodnAcMuRFzz3gWQQY-1744295971-1.2.1.1-8fUMJ47ZAVdntkl8nzqgh.nxdh1Ii.1XdEfa_UZ_PeQTrNfSabx6p6BYwuOjKQReUxWILDUWb.KPRLP2AsXwxgQU_u1t_mODdNvEsE9CHa1G4kioyHrOpmftujWrzqq0TPeFWyAyQFqPyKeAOBEuJjGopzuBELvGyZ78V6Z.31nD6GzOQkTvktp_p.DG2TuSNjxHbYAC8Xy8VN6ZxAFPJkTZs3DNgdHRjxaQVD93z6knA3_icxsdizU_9Erta9gpin8MfXvbGqUapxATVCnfygrwe8m8Oj.bRyfq4.1pYSNljv7KiGb.xsXuAjPdARIoTUyHn.d2ZGTMDBv4uKvs8AurbQEhFyv4B.kVSTc78W_n4oc1xuww1z9.fEKU5NaNaZl1lmjLTP8NQOoYHr0mGWf2Cv5PWyq3V2ADHceEUXjTcYIm.QZbeWOuNmSZlZ0lcOaIw9OFK3b1fo.EWKyb1evB3b7gk8xQX5MYeF08th.ajpCR0lTSdZwr363TET1nhWwd5yMSk5wOSHA_zlpfYUzvXZ.jU62y9u9cOyrmPNKq7uaOWSQAR.wxkDXJbUt2UBvY0dB2MPNtdvAIqcf8gtXuen9TIutzviGMRsn5mkAtaW0GKk.8HAtG_DKsRLQ0nzN570rLDqYuztYPRwkIDAkYDgU.NNz0XBhUapOLdd2YWEfCoIcWfX9RgaobAUK.cKLSXPd4pwo9xLmV2rxTZlE5FLurMpV2LOa9x4Y8HBjJ7IEwAnzXTep1XQFMGUCU4Mvamt2YlD.2XmRHbE0p2f1w.VJ7S6yIQ8zb9cTUC5pPg9Tyc9yhB7yDodXFfaGvqRZyW49_RHexXRL5kSh_HR2FMztiQp8iqQGwcAAk_V_Df.Q0B6lX1N8XCx_t1D3yYUvRb98_m61hfPpeTLU9_5zCAXRBzafvZ_1AQl4b7b3wb2nFCMUTePjMqP6sNI4yX99Ml95Lf.drNWN7NYvnc4zg8wPb2StAqeI4svh55fsToArImRnOdAiCYW5H26yIL9DDwPL2mNZMbRXP4oV.CU3gHvzA4H6qWNIiMR14Fzcn8pUCUA.FZHVTT.jL7nK93A5JtPxhVk_XH3Z6vbF8Gvt.ZI1uZCap8FX7Z81FjhjyX867ePNayP4NiVR0tJOGeCw20wQJLBdrs3JWLB_0LYhMBZM33xYmU7MU7kVk3NRHszO1BJiso42hYNZhYjGA",mdrd: "TY2gqEnALui0oyE3LVCRCLbNkPH6DoRSv.Ioi27LI2Q-1744295971-1.2.1.1-Lnda1h1fAN6DkKnz8zpJNZ.7kNYwHL2NEf0uXR1E4sz8MVaAzXEa.yzMMGbJ7LX796289i6bo_nXGADghiJG1xnJgbhON0NF1CoOed.05gMOjC3TIT.LIf0C9f..kVPT3.1NaCm5y56fsCSe6YRhmmtobK8MaRqQjmhb966hVFl0qrN3n.Io9F47q6wJa33oU_Kb7IqnKASEF62fepOnfvkbk7_KX9af_XavqPf.fOCEhFKBJdNfNuMDfM3FiJYDEjz0e7FQTdl_2HpS8FEmP6RSaQOY9RQeH2vQdncMaPhun2wTeP24qpYhTDPCSDR1MAs0uLFIDHtKeoGOj1TFB60Fyj_P31KuzLYRluHi7eo5uJRpptPXTUUjFi5c7pnxiREHwSPD31lMLC4ePjvon2CvthgDhmk9K2WJjQIxrdSkV5DKFFji0JvNWNq_HcipD6BIz2LrAY3yeaA8f06maY6fElIOULDQg5jv1oaMlkirDcVfYb8du6PqnJJOeHBdNO.BoRdGKb1ji_k_NIiqPWocb5ne_QIq43chY.VWG2PmnBHUhWPkW8yXMOXlXrtuSFOD.bVZ0pn.CaIZyT53bdOXVzR3cJPjEo7dinePCV6ZNPRbyRqTztp1IOiOpqCAT7SL_En7Q15x31rcVANeyVxaeMex19h7RaVlA1dgPjZs3robLBWKu2fYVU1vzxnzq6ZinufW0UGyQ7ygPS8AsRhTY0mZ.dJYam0_DYIuq_UKJT5xO6YNt4sGDo664EjPtK1NDzeTG.UCrVKwaxjwWDpGJdBiOLLrzFb2Vt_oyTM75xjjpcXev9MPkyQNOFN9w.Oen2VOzLYTiLB6OTfBL.FluDrafz9pOUuZjR.lYNP1nIgBXuPK4.1k9Mz1AhorWKlMfj1PUSr5dL2iCvuST5pP4DWoYzXri8LVeWzLe0C6q5CWpogPuSHJCdesCbtzrtTmCfj5t.AZPyTYzTy5nN7bxBco8icRvSmVlSDmZj4aA7VHj9XJN8rOv8IEz.HswIfqRz2LuAMkzdLgUERS_6byBVzzxTD8jSQPUS7g8KXRTRfXV1maL_t0nIkyVJTYPCH6rs7LgGfl4O_8YgLYF7GXKYmAdUq3Zx1ZmAEE2pL5cOcY7P5IOfTbuXI2.Qp87jLHAXvk0Bz5p_MKnOw8lobW5aKXnLohptTw9rxGSZEpdN.nz9naPx5kd716eHI0MBEiMq7gSxkKVaT4Hiv_70Eo1iF5T0VVm3Mi8mpR3NDfhxWMKYPWWXCoYieUYJSKx2osKhwiIzeTL6dY7zV2cnMpWUSQZlAP5gHZdx9ZRz7n9kX241zyWTdi4SUsUT8PO31cj4uVuuJh5mVvHeIMCG8J429QWqr19eCV971cC7SL9wMcEhE.fJV2Dxk5bq7kdUBWWoyv5dTllXwUT1R1DlPYqTLbIBZYMpmsdhMdq1cIdANu9zzTQh8.2SwHABiFX2X9Yn6H4gf8Ml9cTuhaRHkcMSJ3t0ZljdVISZmFCz5OKDQsNNBaCRzBeKuO1JY7rONpvkIjYkt7v4mzUn9pzaPylOrPK7kIWc_xPm8QCVh1N2kJCVXmo4dORTqk4_WBdKxzGN_Bgii.DDGhX2VyKclO6VNmhL4B6y46Vx0_NhsKuBhA9W0Oare50B_n_9HvhSE0q0jdECG50kQS0pKXFNdFhvTZF.VuyAow9UEV5nGRqPdUMAi4uPMd1CX4NLJagnUsdLzEKbOxmu0NmDc.RZo0vpZ9qBPzrrdmYfq1TlnoatqLD9gwwPsZ5QwbFb2CcRHgJB6trotD6FJpQNc73gDswSlVWSapXUtf5yUiCc4Bm3RDKIfpJP3EBBVaeL0Qf3sNV7KcKr3Bq1MlfnzA1v6CPAY8X7s.OmIi.1t3z8J9aaWxj76ptopYALN5g4VaN5RBLxvDxr5j94t22q02BacUundOdffAIpekB3Z1VziUFUoFa_uMHojzGzNSCF3tIcLVuLfOGdJQt_fRXZui8LCOq.qlVh9fUvMcLiFNfzo27CZ.udteNTDXeYv0xovU"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92e2fe7e7b8d40b0';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, "\/1416.62134?__cf_chl_rt_tk=ajGjtn8SnlppGwXSwZtGKvXTQDshTMMAJpVaa8xOFog-1744295971-1.0.1.1-xTyjUnQ8.pLt7SEt1or0ThRIPiydi1C6TVH40hh19Xo" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>