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: '92e0852bca53a5e3',cH: 'dhLmdyFEmWOOwtsssWysC1BkZC9zLVHTXQQatcj9ln0-1744270030-1.2.1.1-qBA7.KWkhzlMynXsXZAKb9pcwV.2as0Pldtgc9096CIUPdbs3elN.vlkgiigN639',cUPMDTk: "\/1215.49039?__cf_chl_tk=8EG0We63KIQmxund11BZDCnE0XVmXMNuw9qDMZtwjtg-1744270030-1.0.1.1-GLH8R80wU84rCQXqMY1aQdxoTQ8MXo.Qo2McKfwZb_M",cFPWv: 'b',cITimeS: '1744270030',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1215.49039?__cf_chl_f_tk=8EG0We63KIQmxund11BZDCnE0XVmXMNuw9qDMZtwjtg-1744270030-1.0.1.1-GLH8R80wU84rCQXqMY1aQdxoTQ8MXo.Qo2McKfwZb_M",md: "ak.45EQ2iuAKDCj7du04D9CGy6T88Y5IDsWeKtF9LJw-1744270030-1.2.1.1-F3zUb4sj4qFquHEuJxZYxmYHVtqs9t2zln1D_PXEZIOLKnK1qCzENB0c8nSm2XcoV_uCZ8NhIDXwHj_gKYPdDV6nKBpIQUFeSPCAc1p_tPzy2Sfw2p5jEngVKX.cLqi8D0d2SusiTfHbtU4LEiosu9dTJIlnncRYuR4Zw.riw_ACHrQYt2ftzxcL5CXDBWM.1wnmDYZ3mRx4HYk1T07SElFdKs4QnVhUlefJ53OuvpeLBlby._FXgEWw6zbE0la0PH3jyRN.hv2JWPQh3WJXuRrez8ec2N6xDLsxIuOssobPeomDXflcWh14McQJj_5OywqvibUfaJ2UejKEFnjIsnQ82N7HKn79WWw7.rhT0kOgpNn.Y8CEK_JowyTxEpqiP2RP11pH4Xk_9OjA1uBolcjFg7Wh0b.Aipu3BePtO7Fb.mtELcAX56RrHvF_iB7NbphsuGN_dk6ANgANtAt1fLAdPrwG6KGfQG5k.FNHJwAqLa2lKoGyZ9ygDBpIreTWg8hFrE11AAD8Vwua1eMLyXfPOg8If_IoVjhvxZFd4eTt0HTI7DwOBchnROplj4ygBxsybTXU0gOmH2au2wM3O3zeTV8R5E5bhuq3mu0Hqtny2SdvSkc9tFZ4ZedhiKK5Y.T.i8pEp8jnYXEYtgfMQW4yZBeC524kJxj3i4foQ26TZJMRu5sPelcgR31JAcg1JdIm7OSdrkygirPXYYh6LA9l.jYf3TNI8uV8T33ix54Pqdt52OEl0fBxef2z2DGK4j8CiFvlBPTHiVodA7Z3EjU4HGuNsr4R8LtDoMHIGwgl5KGRgeoMQIoZGSs9X_iDC6ZxgXk.NceKj19s3ZaLorwN7hbD_cF88gGmsLvxBq9wnfyNQjRl6BRRd6w6BnEnpuOeyV.V0NDJkP72EbraBVdm.3YERtVomiTjLlOqPJPEBe2rY1rb_24scBhzr6bzBQ5T7qwqdL6j.iG8W_cqXSd.bgmwx3ay.oUJee7ei2LlL9Z1k0e0ZpyxEiYZHiXflk7vT1mRLq94nLCuHV1U44Hx1Sw9ifb_oJ6LoDUFBb1LlJhMVsriy5Xp046mm5XA1vjZ6XcQ_JheWZ5WtkqwvvUN0JpuOjCxNtSwXrPhq39Awbgua1Y.x2a0yzRQvYv_4.MI38z95y9LFyXS00_.arll5mRfKcFfDN10WBLYUrn723B6CBUembvHralt5qia",mdrd: "OLCQOaXIcwezYDPi6KNj2BHJK7FyEZifn7pNsy5XNPY-1744270030-1.2.1.1-9g8qkmthUcjuYOqs_g4R1tOTI1w4QkpJEK46OT6xxq_qFav3CbDaheR8SY.Rr4Mpbf16whk9Ie87yibqmrn6ZjUkp.zP_P4EvkTMLFLfrKl3DYbHinrggmG52hexLkNBTda5_xw8ngR2YKi8vMnzICQ5nh2ECN8wMhsj9Dnb3Zdz7A6aqgFu2f5IAQI1SupXwYywwFj_rPNXKnl5kynB6U0gPDO5XoyMCg3L2Mr_ycrRe8q4vKca5vGwqNp.EnByGcjesaynJeeO9dzrwM8nG4v8nY3K1EeOKEcWPY9RoY0.S1UYoND7ZssjAaYrTrF43dFDyKsQ669M89AFk90HPujyhrHv1nMTMh7A7ZkLb39Fl5Y.eUJAHLgIrPAwfzFS6xX4.eF6pBquTncOSat2LPDQg5OBiV8h4paZ6xZI_tfJrLAhexySKRMwY1HZKAM_s5c7U7gf8RmPtX7VPeFEyat5GO1kB7pDYnGtCPsX0EdwCdVZccJRQrYZa4NpuUKA77FpStnsVB_DKLFE3D5LFAebzEUz2qcDmQILq3lVzYokQs6zPMvxMHJxqaUiHMgGZ2PYGpy90ULh.2dnEaGZdfbKdPuHJHyjKa7UpRcuF1nO8ORdHElkwaGsUwz7g5YwVIuVjLRyNhyQulsSVfTp7hVka81b6kCh.X8A12uuJhDRaskV_rPcd3g2C_a7eux.IdrEE233A_EyAh58sWNh5MpOUrB6Lpjvs_eJk5y2BUl1ghBpeDIJRBIQEyKcMyzKuoO7pUEUQ2nIe9w.NWgyUfjWDKICYuMJQKCoZF2nWuUG67aldJzBJ6.v.LBk6z5qka0b0f3a7qAXX2VbZZFJ3ZlAWWXpyG0gof_YvBF5EiXkW0O4m.v9.Iotsrv61GdKDyu1fqkRZHbxTgxSVa0OR0byxGBbYNIJtRobZqGMrWPIoa.zDQ2YvNxJX.lsPsK.kKBCg4Vl.4RKQJPhabY95dUKe8iNmSfBBab1ztAXBLIqAOPN32gGp4Nb0ZZgpUDJ5BhTWfGl.3eVnJ19pBbtNAe.zepBrI3kfArPRoPZtk4KjuYvdrzGBJ.Nm73jqpjTBa.woHDjsvcO6EWv1Ii0TP08yxBaH_CM46DLf00eZS4gucCmLUm_sCvptBTpADeATYyBMrMxWIAI2DkD5unKAcYylT9Z4Bi9GxtLqKh8_zAI0dg83iG5d6STjVofzHtehtiFugiBMDrIKg0MGWrJ2JCy5I3Fs8TdO2He59QjeD2mtvbnDa01Q7s8.EBWpXnTyFszUvmGWTLEW0vSNDDt3oHZH8PfSvqn9Fvh_2L5_jz3IYi6kovgGeC2VGyemj_mm6ZRAFzZzsuNbAe0v2RmC7ekp6Mm7e_dXXMAUVQJxgGBvOiQPXj4Fu1iwYtCjBo5qWNBw59ojCjTwD_9ahd28_civ1Mhx77zWJBz2t4LEtalftm8m9FXweRwkXQI.oa1ejPsvL_Ae7SAWhayybKU25hJHsiMakM5obI.h6j7IntRuHmPonKez8huBhUM6SlozfIwWoUN4_gyiOctpjjqu_tW73TjxOSJrfrQYEvhHOLHXH7tVvubT8uRmwALAQKQB3GxQ5WHwOET3KKaDwagbeJAsVgNLoaZMXz0Y5U2KxPBf_9g6y76_ly9T_EqGP08.drGNQGy9YCpOAbJwiLoWovMEpvjTxsbbqpvS5JF26Qk4_7IM6mI0VE3GTsmHG4f4Mi1fqJ2aVRFEV9Mu00qEqMbboGAT_VJGEQT74KWSCv3Q5QWGn0ngTICFgoHY4JSZvcCG5sNflUra671zgY131qzVc.bEVUV8iB0fRv89m1Zgz7RRh1s9GOQ.2d_gjdPWxf5npqm9przNFnzSz15siQz4yrwpefTJ_zHl21fDcAZ3tyii_tf18YCY4ckiZWdSawatQoMR5ycsIC5i6_aH6k4bY9Z7hO7juvMtDzXhpiR.S8TfGmd1u0.pu8UkARSfmpetyNklbdkhXFK7.EMoqPGL6k49fZy0GZAx1oXnTK8mCZ7tCQoFWAy_uGdvnWQ_ekxD8DoOq91m7rdJ9FZ_A"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92e0852bca53a5e3';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, "\/1215.49039?__cf_chl_rt_tk=8EG0We63KIQmxund11BZDCnE0XVmXMNuw9qDMZtwjtg-1744270030-1.0.1.1-GLH8R80wU84rCQXqMY1aQdxoTQ8MXo.Qo2McKfwZb_M" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>