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: '92d9ed8b88888240',cH: 'Q7E.kABhqOfnN70RwGsEsBFdEwluiHaYyNGsZ3b3x.0-1744200905-1.2.1.1-qiERcPZMH.baf0BH5.qT7SblHa.A6ZbiVcNMo9atLhCP13kCcp1kAdTJcqoYjGPj',cUPMDTk: "\/0397.05019?__cf_chl_tk=I7O1E2TgbrGwcTMrT9vBMJuMYSEKnS.ESHb2M_AX5sg-1744200905-1.0.1.1-Re7q8QkWhbVF_jNKotVyHG_3QuZA7UiNGyG1fv2FqAQ",cFPWv: 'g',cITimeS: '1744200905',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/0397.05019?__cf_chl_f_tk=I7O1E2TgbrGwcTMrT9vBMJuMYSEKnS.ESHb2M_AX5sg-1744200905-1.0.1.1-Re7q8QkWhbVF_jNKotVyHG_3QuZA7UiNGyG1fv2FqAQ",md: "q7bG8Sd1u1pPucS_9g_XQ85t1Axzg0HTj9lkmDo4X_w-1744200905-1.2.1.1-f_OW5E2sKpb01.1lS2GxYQQakw1xt1UF0Wttul.zQKHX9wUcIbftoTH88FPPFbBoMTv.X0GEkj66_MCEnDouL1v8En9iRDPD4HHGbTxVhPEtnSWryLg5oXagZg.MJNlvuMwgV_8JWmydfDPT8Qf.GqxHtKceeEOnjdVPlfb5HLhVRtTJ4qD6eoLquw9CxrPZEhIBXTR2TZqzDYyL47xUJIg004DNDYbuCKT4awP.8cf.Ci7qHL2SHwRGVLdX00FHIP6vp4YLL_A5BwmMzt2LxHFJOIhTojg3RlWXD5Cx6vA9QeqG_IiAucsqudL5HQ_RFQe5Wi68xWSew_ut_mI0kxarxal34MLfzkF4Zx6ElOb6eEhzuq2EgUAhA9DpWpdQ6LlGbG9qU93WVHqTGobA_KQfNLIaQtpVTv80NMGiUdR2YO1fb7SDPKn9HHDJzKWNFeRzdIWPGzG_lf39NCk07Ss0HfumOHQLX2bERe2.IygUX1wr844bJMppxPrmes30ZaqvvI86dOjzNoxVgLnNK6QtdPOsHVd3_F8fnt45EiIGQia.GA5EjOPvLH_xcA.UNeH4WNfuypndSyAk2AaGDtVjwK__ILWiVQr1giduFKQv1o2IszYDlSBGkHnDRj6.PQsaNijQAuaERCBErxhd1z8Zgg5OUv6SZrEXbCWiKf8xy3zP15r9qoTyP6gtDBZMtjIgBDbL.9hz7NKFOta.lUeLVQkbvd4yl684D9whNDot1pu8okqjBJX91tJqp0fxxT1FH8sdlSFGF8lhF2DYOBZt0fNuXcFl2GHloL3AvweXKZH8.E_R4odcCCfyPhpedxFixe6YHqNd5ZrqVyneE84VyVs.FxqRyzzvK7Y3DJdvf9pz9BfiznBkj.gqpqiHpxtX08Yg6vQ6sT23UuwYVTxqKQcFwuixHIiL11Rbksz3pJCcHETZYvXtySeqlZgDPwMlv3I2G5NqYpXuetSPr5aobCcXDS56ukxKJahSyWCejhakhhhf2KGxzE3VpfuB_DMpokcAMmx9BymmsGKm9s1.vjL7XJ96HUkaDtJ_M8aze15wnrOlqo4gqUDKeUZNQ8uLt4b7RDr5xpX1wYnI3KKdOsEM683NGReD.U2hWT9t4vowhx1c8u_lHnPmnr3iLdaRDq0MzKzPAXR7muqn3qCVU0ymiRNmC6M1vqEbgfC26KSmD2IuZCV_Ukgl4XVQ",mdrd: "luJuMvxnURzJBKz2W3NlFaXCQrYMD6qaFCDLU91mSZc-1744200905-1.2.1.1-SlEVTuksqv8Lh2JCbzu8Yj2vx_zDyAQBX.rM7oZqc6Fcd7mYZnUR2OSzBjakazhrXD7aKK_v17GAM..syeSHQJ4XYCCPUrGklnpLm5DQOMC9N1q4G0u8FwpX8CGDn7kCCFg0KPohyd7CmGUgezotmjlRAw1XTafb8dnBsT7CmTHVK65_CHKXHGuuoqQQSPkZrU8uD48k7J6q4KKZohRI370qlbF8zA7ljDVJLV5ECjEkk6ld3Cuq_5wCdCp2eGrSYsBv56KZ5h1tkf8XAKax1We.6gs7YVWmjnAWhaPt.oxLVKN2z1_xT1_dgijE5Gxd10R9ZbNCIwkFmm3jPZbUZ2qW3ghqSmVBXHyicdeXJxj1xFjhlxbsYWD.wDT6CTjr8Ty_.Y8BGjmr640YxdQL6r9iEe9PdQFQhux9iNXXmzJPz70bUUQ5hBiULPHdZCF337MP4sbi.F90a6dwI1AGpiiG3IKdcbI8ZYESDFAurpzlSz_VBDA1NS._VN5ExxfI41AHO3n7l8VvnLeUDMzzefXfamZ5VYIWx0gwNn2v4C6qkQ7u5HGiy3j3abj2vbwE799u6sviJfh3Z29RNbxzFK342ftr18E73PkXmj6KinR.6iytytx25HZMnmqgquUfgWMwCWgg9OP9AH5OQfZlrK.HZjAigjvcKCEsLbbFYu3tCeNm_3x8k6kI6xP6_lcD5Mq5CL2VpILrCCTXl1SzZFn4I4nWHchanTOS2s_1oqbq287VQSVklj1_yWEWVOw9ibLteN6Rw.AFn.8awGU7ZKt2iQaPnA89c8504kLiW3JoibLxusClscDYx8qha7dKVhZz9bqfGv6ozSadGm1egK6tLbRRxO3ihkXjpyo.S1Xd.4P6Jz_z9X0RzPQ6As_nw4XY7.tGYJzLh1kneYw0XAbCaf9XixADOG5MGSvc7AtBtGNujV2PQX6IG4DsqbRp8vfOus.ex2gIRqR0lYztE8vMDFvlpM3XpAMBMVtBeo0vuwViPejCz2vObVTP9yCPpfXiM1nzi0kd0xultbCeCwUcIbY0sXTAc4TKB8Uwz5bnh9Fzco0e5dNp3ZAflnCacdWzBvmV2rKHWhmTxu2F5Jr..58V5wLjRg5DBXC0LHyhIz6ES7XMPC3QPK4J67zbQENiwJElIVeeYbPTjA001AcjZ.DPVrFDtV9XtA6kfHNF57wf4sdDYJJCSTxtOv2b0NAiKXnJtd0Kxe5wrboxJY0439fvAzshx7E2_3naN_LdNKTCU_afEo.Ujwl6DH1vWyYAoAHCDTOi5MGR49FxivThx0Z1JRe736g6RVRpX9fMNAbmkStN9sC9cLISIrNtHjaal567vn2s97vcTW4UjOWrtGu7fNeZijwPabu_T_VVnv7ilc4d4LWhs7vcrcOVoP8RlXgnmXyuP87lqzBypCxIviF2PMAGLGr8EMLl5FA2ME9.9SUXVOC9SuPFBPe4ZRgsr3VPfMkk3WGxuAnIXRytSATXke2qyMxsVd3mxSYq6CDZHDkpRBqIEbj9TZaE_dFqJaNbqlwuiOTXuDShvd3Xoj7caynsorHT0y2eiYUjXvs7M9UI1YIKEcoGl5bPj74c3po0.x..Jh0Ebg5oJxHNGSr4HrOcoPtfMkqDz9Yj4W2IORpVqrFop0nDKp2FUjDa9rk10zbqerBbankeR3bLpV6h5FdA_z0fVYI94QetHpXTUCesQQ6Bxd4uBrbRspxFnqB8W60C40EpLoVAeOdpXeLOZ2IP3Z8wN25IJd1vY8iPOFFGncN4NwOgpjJO4F56atbH.pVm74Ki8uaCI4pEJDwVe8As6IqzFde9BJWXfuJEDNGWv3XyYy._BtvPO9J1RYHcNMFKHMWHf9mN4lgBwm7dQ78rnTdne4_6N.WSr479SnEPP5iwzyShIeaF6bT6sOYr0z5vqe0bJK5f.C57vVXFSJYnueOUvmk6lM1eNkK5jo0srdN1PPKTuOvBWZG_5xnupOU6a985OAEwyFiKmqkh7olhT7q1je2xA2nJCJgNol3WKcHJ6e6qxkoXdtgJhY.MQbSjJb33SiajZQ"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d9ed8b88888240';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, "\/0397.05019?__cf_chl_rt_tk=I7O1E2TgbrGwcTMrT9vBMJuMYSEKnS.ESHb2M_AX5sg-1744200905-1.0.1.1-Re7q8QkWhbVF_jNKotVyHG_3QuZA7UiNGyG1fv2FqAQ" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>