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: '92e01434a95f7ac6',cH: 'LNGtIts_gM1HpzJFrQIvzf.IvoufKu6xbUBCByyz0k0-1744265403-1.2.1.1-CazyFmlawJMnYhJL2rLrQDDJv35GrqQ.n.nohNO3kG11NXbQ_FVYBnFYki3iqBIL',cUPMDTk: "\/serials\/1931?__cf_chl_tk=nOY.Bo1dt1O_vTl8u_VRcSHf0SQyvTB0KUcKn__aB6E-1744265403-1.0.1.1-kO6upIYmeFog266Ip.kFe0HrIFwN9bxSax1bW1VbcZA",cFPWv: 'b',cITimeS: '1744265403',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/serials\/1931?__cf_chl_f_tk=nOY.Bo1dt1O_vTl8u_VRcSHf0SQyvTB0KUcKn__aB6E-1744265403-1.0.1.1-kO6upIYmeFog266Ip.kFe0HrIFwN9bxSax1bW1VbcZA",md: "qGoG9vwfx5nygLefnnqKbA3Nt39BGrWMUFx.KPgjsgs-1744265403-1.2.1.1-MZEmrmb_CnBrqeQyL8kCtcIgXffD_U63BYpBhTWJxLTiIq7RaQO9ICp.Ia0fEq8.uGSgIa4lJWnT2cErb3C6jLbwzt29HPLMCJRWtO1ciVe6iCpd_F06T2U7TxN7IQ1MrSFAiRS4wx8Ay72_UKLBxwKgL9igEWd2DfGAyHiPVpnejHAqB12MvWrIMFUCDQw_Z49zjN8lUP8zYpDEiXJeG8aEFhWlevuiQJRuh6xFSRsB37qA8ckg562Vr_Fgjnj8wGGJefzwtA6mbJOQXoIF1VxDnmbTnmpxbV9gIU3vDqX2oIYxYkAl3mOL3sNEeUT1RCseCR3TdV6U2nR_A_6rRll7k5wObUAsPXlOvixKxHi3_BFcpi6ebIto4hXh1WbMLD76AXGbVoIKPtYXTpa1PaSMqgIXFO_rvF8jm9ezWfMH2BJTw.lRctLIWecDlfXPInYSKoIY_lUFifTneNFr4Sh73Bd4otcQfPxgSiIEkTBvLHnXAtcwMrhCrIhFjt0yxZRlNKuL6510gfAl_SBtFgPXEwD7Es3iA3zjlNoQTHJpdqU1iIQczODHCz4sJ9_cziQ_oDkzaOg2RW5u_YqipKEUC.kCKqWdJOoIP4UOihjQg5SdDH4Ihm49zw8W.PUzRoIxzCvQMWVmuZkoR0hsZeEwI5N2JnBQR.5QTW6swdHNbxe7J30FPiO2OT6AWLRvM6UbQm2lL8bHGSuH3qNPbUvbnkSQKuRoyHyFMRj4LydIGSeVe_MCk3KUlmFNi.AE6SodSuswc7Wh0eZJcH9yH2xxQegBn3IGML.CGhnhZTyFZPSsLWlJcpTNsM0B5U1vXQgHIEwQbHs4OhlTX2mppHqlgGqeUGCvJFeRwLUBOG79l2.MGau6P_z_ToD.9zCdxg_NkhqIAzHMKE3GGAumU8ZeVBgwsxUgWElRsw3c40szuH8L3.rjhi1y04AXdoth9BLr6FRXWWO4GOX05uOIwXlhHbOJJhRLmyVfMoqnR8J8mnsOI43Ix7t2P9YHlNcAavOd6xAivO62tWImdT__V27NICtBvlLlIh0RbexT7FQmVwh1Wi8JvEdElaj8.qKOULDSANu2ZByADp5HlB_kJqSM2iB_zVHCN2NYzYdw0BK1cE.8tVuNV2hJI7GGEmoYQpkHyNXm9AVMVzeIobZ6GCWidPLtcUvEeluYhRsdpNDroqYkbxcFBm.8mnIERK15",mdrd: "t19squazxzadjOexgSs3UyABrugDCt3JsvdVEL6unmA-1744265403-1.2.1.1-dQyhAwEIHl824gDqxqozCn0Ma_tNrnIDQ_Rp0JbQrOsnEMDjVZwgW1nX0Anaq9E8028v5VwCD0nSAOicIYtwkv5Gb1xNrx8N8fFJe7Ze6MQHe6kbY4tOtNJwRZix13kMPLt4K9ntj6jLtbuyiSs313gdDsCAeoJj6OF9bH4lK8.JmtjZxdBlDAVfDJzEs83kgZXdk2rlHT0X_qrgrP1_7Osw7_PozBS4ziFGNqVGlqhTeDjx5w9zHZW6cxTk3tHUGBR8N3yMNFRIf2N_o5zANrp5Dzyl75QI8dFQNOzf3yWPITL0tfmBfsuVWktAxkn1qd4YNnf3VemkaIbjj.cd9qvzt9Z6lCADdVYg9zAR_dIwHthKFGNZBop5FNftq4Yu_tGV7vypHZdf6ImLqXYal_mMJW4TLrDwFdjdL2QnocLi2_sJFGgaCLyzRZh.Fckk_YD9gawZhICEAOtdFP6JgebINLZHqM53EIwtQEZZCeLyoMqMorDLNEZQ80EJEa91zmLe0mH2ewN1yM9ddaeA3by5.wFksE8Gh2VGUn9r9wjMai1DeuOnxSl2kCoqV_BS1ZAJ67Iz4FoIuJ1VwT8dwhBc97sCqaXlKEOzgVlurGCTS6l_KH6oPmT3aRQ1yboAoAkdi0gDntD7YpBgZaD5g.OpBFWa1AuU3IjTkpLzl.3tuZw4EQcKPX9qXxLYOTeWuu035YxcF_Bl0s6eLWjTbULo7O00JfBpcnGMVyIRMt4sHPZQw_vifT9VDOV2JIySKce9EZBbRsSkvEu.YaHTcycUYR4_8jvfJGihyQW_e6AhkYSKqKDa.6bEUi.MzwbAZHMHA8Vulnl6dwmFtM4Vfx0PQgjp54rcKLzKnwgTut1f.FsMqrZeaz8S7GqW6cvOgEawMdwIvkIdbYUVXh_ZDG3hUImJI3.ot5ZnxpUekbchijVIQYENmYRX22CVEMl1iDgv0x3s7.YppafonCE__crIvtGEO6s6ZXuU0E0i.0J5Y3Ngc_KkILzp.0IX1M1LSfQpA2X7.6vUP3.k.8DhP8p4OKjOGe56LpcEwPoZBuCvIWuH2ySDvaTHQqMB67K8LUkH8otJSCTobox_8DnVuQ1Hh1aRd3D.eIlnYiEWzK82tNqBNwcm86SlHM3GRPYrf7_ue3VTeXPw172N4LtJq_KQTLOoCP.YdT.lPOVM0YTUoknsEMtHfIzRB8jOLT6jKAbcqwugwU8ez1lf_91nOpUxZr289yu.31vvPY.QydHdI1WuqPqUBBmlgOByOZ1cYfL6y3Kb4a6MPCFZ7XEM6m3ak_eSrtS2DZ8wIB5u8eUEsn5glJuH_f74gIcxmp3_tAc09RqBTUpbq_7tiKT0WD0_Wg8bHPJDM8Z9zFQLpPz4x5FWOkOVflNySEH6Mm9jkRVefHA7KHDpUGdERNtwRGiempfBJ8e0upmbtS4WnwspkokLxJgX_Q36ISflYxmX7pklPoRiGlUjw7g4bZ8o6VBatK3oARSzCSJc86zxZ5BSEq38ebGmL64iVrzwOPgqldZEtmGoT0AKXa_LCUVBE2DT39htM2g2GLgVds2O_WRX5bHuhSP3Jm3.lOGdnvJPiSlLteO.yPAfad7snIDk5LaqIPF.4vF9Vrpn_amkljtJCxZ1eqmCAn5Lps_chduxdz4Pv.TRWKo2V.EUPdqAIp9wUcGmip09DOyNp57Vfs1t6f4RrIbu2EDIBDRLECE_1dZoKqcOwjkI_GMcT3m0h6ohWchjGcBElWKy1lYA4rV_xer0BdBkDfegqpjt67Nqgo7uA9R2Rq8EJxOUdUOZoZI_HOIiszFcGYS7lyyQg46FeRPqsMuFZd6Wk_ZYPKzNf_RXWIuNDBxwFmfmNcPZbSCr4m0N4KkpODcxPZD2vGjkyCSCnwZT0vFgvgbLWBmX053BSzDKkqbxM9d3Cyw_Nh5ja5k8I7j4YYdDS8MBD2wVUpBxfgQUUiKHmxlpg120fb2zZ4Mtl8TR5DQANgE.JvxebjeL1YiSvHcxDN0foAfDPDtApss_0pxpBUYBIKVH"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92e01434a95f7ac6';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, "\/serials\/1931?__cf_chl_rt_tk=nOY.Bo1dt1O_vTl8u_VRcSHf0SQyvTB0KUcKn__aB6E-1744265403-1.0.1.1-kO6upIYmeFog266Ip.kFe0HrIFwN9bxSax1bW1VbcZA" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>