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: '92d5fd12cccffdc3',cH: '6SBfmYezM8dlRo4xWEJDQhupPreC.Fb5ubq5iOY5CqM-1744159598-1.2.1.1-PeK4_O1XST8kSB0HXg7rlJl9vgBi.ED4o1HFRGIpTNbgz.eslodghSyg8y8S8EeX',cUPMDTk: "\/7959984?__cf_chl_tk=05.UNscvZi4nFQ56wtOehg3j1pFeFOjcG3utJD8jBMo-1744159598-1.0.1.1-nwaTknePMNDk2X.6z2NeJyb0u8XuwGv21q1JLveANyk",cFPWv: 'g',cITimeS: '1744159598',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/7959984?__cf_chl_f_tk=05.UNscvZi4nFQ56wtOehg3j1pFeFOjcG3utJD8jBMo-1744159598-1.0.1.1-nwaTknePMNDk2X.6z2NeJyb0u8XuwGv21q1JLveANyk",md: "JjqGyhe_TPXEnjo5sQdwv587Lvqvv47CzTW69pLG0gc-1744159598-1.2.1.1-gkkR8gJVy5yMterbnW6LiAYHy5M4aZAIdDPJ9gzIXEk11eoH.28y4WwIenjEGhKsqrbfRQxPYGGwQnXDKm8Mi_nX90Nx_UKvfrYLDnvV21QgHUdord4qryI.tOd_HeX8Wg1ge3T4MyT1YZ0IgbPeSPOLv0L1c_s5ABct840.9q5pYD9.ySid58Ga82Dss0kNub42M4GEozohKQgv61yWb.VdGdLUSG_5lBUpuuDt1RH7kmxnTGOYgRuQXgPSb4jytp3rFzUxLlfA4LTBHwBRCJF0K46vmQBAlEJD1rMVMy69ecABQ9jdJuHWfYDsAe5ZBGNXXtPo_zH77Wmd3REqvUl4.3br0KdBfLAenoGpYcLEQxlHi_.jmuDpOST5JOF8chqCvQiN1rv1.By_4qq.vRS7R53b0k5bje6yp8Sb2hxjWrojTyNEJWNEvjXGILlYyfOYMZEjQxs_IEcEy4fZjaFdwaTjNS42O82zaNTkAq2yZcrxB_KGWMe9b0fiPnq88qXAf4Jfuv8HQXiz5xv93ezlq5YSTZpdmMwSMS2_ohkoH0wpFxpA4epdkrDiTblnIhsT7VHXcis3TXC_CuKNWCyAcpzm.c8CjBocuiNCItFnvHjMtv0wWcYoHFOCuafZ_hekdedevPr1Ighv8l0cCrZ745DV1VGJ2bSNnCvNlZeL0Ze8sa8QKHVZ6a48A2Wtkd1G8qC9gSWo4q1liRn0KUM2LXSJyR0GHcEg8kzUsYf5wCsYx4ERKEiE32mtQPylDIHTQvHqu7SuTBVnxcUpkrzaSSVpSVCVPBiyCa_5tyRXvTR_XIx3_r9vyvdKzDwmCryKndBQ.BRmi6qwEQxdLtdtImLVMzLCS11MHuP8oYnXNWOSH97KKwJRGBLN3Yjj5lrEO9T7q4oBR6qKdfvUqAahZkteSpyscrBa25OoL17uoecLcyR27qtSeQ5Ja466taqwGQD4vUP_FfhtUqr1TEEa4Bkgwe3WQSSuZVGWlSL8Hv7TAlEcsChaSd912ebS3ziOganPa9vPu5ZvvqYqCXNCwqM.eA12R5oihcpFy1eyDvbs5g73wxSLKZ6uTUCHoEHADb3XAkbR3htL8_zcqYGSRrC_IsNR5FRu9jfnGPRYmxX8U_vQJ5o50aEzf.BSy2QIRWlC3smxW8GnJGXe3Wd9rMcQ_.7bEzsrA99t3Yg",mdrd: "Z2tweD.5efUt74NMPSovXQBYawc5qV.6R0unFDIUSa8-1744159598-1.2.1.1-Xe4QsPv8ffJhNMQ_c1Wn2zmO52XA2B6NHmN8g5zreQb1j0L7e_XEiDK0fQkYxwSygiEB7nJKWbXJ3MezjmFzYeUkmVmM5klmNo6V3RgnPLgxFSSotsiC8u74XrWI5Xz.TZt6U0C6QtX1tzETstRR.pT7fxAAZVWZsmmct4DuH1qa9e5Xt6wc0zLKHaDFy5WAMAzvVtRSYAAXlckFILAUyT1r84.stBAzKAVA_Egtp2BFPCZNr542NnjMiQMwOLj.9v6Wkk.g9xUseschTVs8JGpkb2p0gfEVh0NJScO5piwiBlXi4jy52lHfSzBI7uB8H6aoedXNHhab7VTVcEBQr5U4s6ddlroaqZXCbga3dAeLN0IfY7BGcMPO.ii_U53yIwodoSyLX1vLiSZ3F1Y8ose1sDczBnhVGvALpd6PL3eurcThgq1o7eKRFD6K4IE3LNu3h8GtS5vGWoETRUGdFNeBb9jIwsdbJUqrmME4T5MoOaFuRU_CKE6VJ8y.pdQ5OsPlJbBdHdKg7Y_g1S..phuftQgNaBFConD2O8lGO.QnMCz3qqp1NgHd3Hjse71CRWax4LgvIWZZAcZDwGOBETHQVhpKB4DcwcJAFkGuQSmlG5h4dPkPpgOcySLKZCo1LmfPJvcDe9X_M4zVQNtCrGnH..7jwTUlz8Bgv0VEVwiX9pCLbX2h83jb1dJ.6XyWhSVwCFTQlt4KVuy13gX7u9zlj_HqiOflb0zdHbPIcWJh5qAcmrwYcJmQwkDEDzo8dWs.MFZpN.vxuK_NQozPYZhlkzIGFzohSU5YPRHo3OFxsM4RnllWDHwLx_EhA_DxdrBv6waO1OiFBdO88gUKao9NO3Sri9ELNYnmqmwJB0CspaAIQXHx5zUFiP9o4tlDwDzo.i9IyEeKYRwtc.aHTqdy9lTU1o3LZIj27Zh1Eq4q9jegnTA1cACvHuPUqL_r8hXWEwVivKScnN8qjBUAPr2F2R.4eYnpoP2l5TUlghfF33pbPmASF9HsSQXBo4KY0EC.m7XtAVucV33JKA5BcSXCNV4n6gYZKCU7iEKYXL.Mc.WKA4Qu.TrnakVIRDMlUTNGytgs_fEKMMsiz_OF5aERKGYt9V8ZbONopazBqDICHGd0MDtQSwFivjMqgk.NfAoxIp44bSD3b2AbzRZEtFrDGBSFXlrTZTSVShzlRJjSnEnsVTzA0QGqaJ7nHCmrZ7fpjHbWvT2SY5movGXINAwKMFBoN2kRc7Lj2hFOiT4pio1dQ53niNtNWfn3zWS5ne6YUQJEA7yBlwomlT5MSDOsE1yDWIaLG1M.ConLi41uEMZe_wZyw28UxSPCEuNNyw0.mhGXDiCuURvkktG7ZpctGIyCxSXzR646IDMSjEAFzlS3qZqolA2XhDk22ZdZb1CT9H5ZnwFezqsehmTq9ggHRQGGsq_MgIFPJmwNY4NA6gWg7agRyRtUQuQ6LwdBamVid37MCdh1QGw8L1ZkqVVDOzIe3Qf1p1QN7cgXAwoBrG4yShNOHAsRZ5HsEo0l5DvU6Ay9iudBl_KLBEyPXQLoHy0rYRw.Ww07mL5HH4NzHWjxnfdQc50SHssAUu.Epx.Epsh348lFJyUZHMQnCuHxaIEpSw1XR9KOUavdBS0ijNHVv1_zJSTjLOaeiHipLdXaocdPVOwsiviwUDZnOs5EG8wwFYGwBDIeCRHw8.Z5LG_0qhfYYmzqbE8_pvcAxn6PRU7cS0sOHxU.Mc4NnHMwC7.1qY0IqYYg0yrysvmzu4eelqS69KaonADTG4Xzc4PmocXB4lNVzPCEt3Owm34hoHDY0Crzw.n4lD0PcJwpGI4_QWole2Uuq29ebyfcIqz5Pnin8.gdQVZIwPEcIUhMuQ.eSfRX.QtiJrIHZrz.pSCOE070Pzw8m_4CWzQGsvpDIbSlpFHG4hOKzOLLHhsN4V8syGXofea5ZrQOvLEyBRYKbxzLWgxHLhhoOQKosfhHBmes_jNhKtqH2OKk7WX7rJqX2PsC8QfYT.YJyhYVK0kG9Yt2by89sY4r.dDy"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d5fd12cccffdc3';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, "\/7959984?__cf_chl_rt_tk=05.UNscvZi4nFQ56wtOehg3j1pFeFOjcG3utJD8jBMo-1744159598-1.0.1.1-nwaTknePMNDk2X.6z2NeJyb0u8XuwGv21q1JLveANyk" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>