CINXE.COM
Just a moment...
<!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: '92e54bd67bf73dce',cH: 'jG5V89H7j3gJUhknFrnRn5gscC9kyFUaAgp7oDbo4V8-1744320111-1.2.1.1-8hI0JvbL2.UaLLwX9ZbS.Mohq0uNGkeCAIAbCieWNsFTYDedfN0kUYpBg98BnwnU',cUPMDTk: "\/authors\/he.wei.1?__cf_chl_tk=DG4Path3kJVrnnuM85oQeI5B2Ev2NSTul7IrXqutCtE-1744320111-1.0.1.1-K3shm3miZs.rilIrzSUq1pD8HmVxtVneQXxNFkoM5lI",cFPWv: 'b',cITimeS: '1744320111',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/authors\/he.wei.1?__cf_chl_f_tk=DG4Path3kJVrnnuM85oQeI5B2Ev2NSTul7IrXqutCtE-1744320111-1.0.1.1-K3shm3miZs.rilIrzSUq1pD8HmVxtVneQXxNFkoM5lI",md: "NQx0hAsqpWH.dfD9.Wo2up.JA16ocJPDGTOmrb7cA1M-1744320111-1.2.1.1-guO4ZK5G6nqyMNzijB6WJxem8Y.FWEErIyVyXxdJEbSQtYqRZos3bGmOQuUBd7_m7K1HHaUL913MHafnW.4zo8i_DBLYTFFJt1ToKBlPXCzCuuRCm1ngeOTDpIV8iYbD5I9G.yuVBvuMdzX_1xfzZUaWCzm2UN04IEfNnDPdBs99mZ0gxP8ttAW0kVsAHtzwHW9r6XA2dYO_VPpzHYaoxE7GXiPj2zNOYdpbNlRetxPUFK8DNQBYJ0DasLbNpS70DQcFBgqkOdrQ9s_UhC3pQ2Ozkda2RC0d7Ab.Cn6PPSEujbyj3mxpsBkPCc7h26.3F6XtuCDVp.yhMrDNZKiz7PwhqwnDfj58YitDJGMRML8lhOEV039Y7e38mciy17auGJ9dloPZblkjVLP1g4iW1GMeZOgxzntsI3uB7fWHGOiy66XEjT2rBfg7Un7dhOsP4uA9DOhYseofzm_5xfkSj9gyK0KAHTGfeMAT.Rir1ChSimALHzAfHcCTL5f.wq8PIwrrgovfaPEtjRI.H__zZulKJ1Lm8FNrs8PW_Jj_x4NedV63EvkspwGig6xjIsXLBO8pmcGkbU2vKGzFkvXOT5Rm6790nCsq6qVTcs_1oELEZVCC6XgiP8juK6Gf.yzrPcp10HLNsrvxsAm46RXLWXwN1Vrm6T9ND8Z78UBCWsIgvyibFECOSwqFrMUrEynoOIGxy4RNH053RgwwwkRXd5SL25GipKyo8aSPdsXRcd0C9UbU7mJVfhSxFVAeMEZOUlM7VxpVzvNgFx8WRKQqThbE_kWl9TT8GpP4sZtQsw5ixiliv8joGtjQX6YbzD9IFILpv0iYoZhQKGmZRRbqlhz5zvyRjsz.P84iwUikzGqj2uFDnJ2qe4hg3wSZoElxx2n.5YUVb65QZRmNICg4C2hRIV0PZ76kZ2VLYjC_H.P2c97X1SMB989epvuwhQwayjwKnlAqqzCrv1u9EQPOGQ8OEcP.B3P.jTXXRdBCCrAvr3.bLd5UcmvVQgtlvnxAi1cyptkFS182YqK42S3FsFJM.GvgAYrNFkPugkSlgt8GNU1FHcG6ySHn78OY8i3ERtnI0wZ7WRSjD3DjKdEGvC94bwE0i7xCH1AqKkmnBPMu2WffwjUOHg1T0Cze7ahb3DF_obyWtGSu.0WEo.dTp2l6U1WYF.X0KUa3QCR6Zr7Dj26DUJIpwvHgCzJrvT3fZ9hawZIc1eXwAQQp.CDhQA",mdrd: "nUAn_tYoPnLHhl5b447TYoEMRbufyZPFQ4WLe8Igbdo-1744320111-1.2.1.1-hOQdbJf7Wxne_s5rHKmCBHb0UZsQ1DsuLGXkXhhoUxRqMS1RALAHbKuTDK5W2AodtN6dO6FeMf_EVnRMmIgtR4mfyi2Cs2i9.tDCQ7HP0gmIUnwIEIqREue3bT9XvCHP.q1Y4kA1rnfigzrnPo5I2Rwn0bERAuc_kkloffGfrzBDf6PXYimGroZgeaG3JsHlC1b3abtMXnUcrDHWfEPZ2qQFN8SjbBw8RHnBwjqlwS84yaA5BXdVs_lnYeF2GMfC_l9scyDt_r6kfsvu0xM_w7.jGOWvqHzCjI7K1iqi4orhF_9Z6uJ5b9cH2.sFMpMrWjO01UCaAFlQsoKSG46pXXxxjsYaXm4DiiWUOT3vfm5kE_QTjsHaEI7avYZT9jrZT.VrJh1XIAOfGXno9rXHcPqYXx9FxmqcHqBcwPB_vImGRmetlRcMSITp.4rhiEus_ORKTL0xLJoRUHnX6LSGPHwmn6QSQhSIZFA8Qw2Z1h1C1R5tu8AOzAxqS3iig1UYs8LVZBGUb2YGbW56UHB8VnbZ3rJpd7MXX9YPY6UkF2yVRB3TUYCk5p_YL4cvCmQP0twBNpOcS1K_I1cFuPnXhFtUezyU3.gFRfeAojiqvl7W5q1Mv8DQKPvtlsSU5LSCHdZnHsLSEepC9dF8bokaSz4IAE_3XpKFOnmaWdRPYvUUpR3STK6KfVE6GuwfFd2O5Ao3srYoRz21.HNMsqAGFXZ4kdck73rWVho4YnuEnYZ_jQ4wvy3Uw_UEL0Kqu_Esi8GtQmjLJL38oJdJGBlxi1h4uy4m3Wgnkh0RlxLKBrimZVaV9q7Kil16YvKUom7F6Rxe1P1gcI_siKDvR5UwoylSHhq.EXfXoyBqziU7yKqTbHikyHliLDOf5hWH8CxXY7SRfoGxW17fP7lk2YiOt8KTmdqu6Q4M8zmgTskmX0wz5kjemAlwqBiFXIy6hLkwodfwbAB3uz5wAEpR_zBC2mKcyyHEcDjWOCq_B6jCCkLI5jBQHZgb9HdZ5yTwAM0KgD7PZp3Al0tYV7Y8bDv3KZOtpaibgnnZ98YKdoFBUb4Qy2PoVNvZWEzLxbfUjQU6Kub7IHRoK0pilQVKTcX3gT6hRDSTjqrCt.n74.O2QP9Jkm0QVI7iqMTeWYeRtRB4W8niAJvtOIHDW0e5wY8o5EG32DxJfLC5SLCblkfD01jDxZ9QZkijr2iYAhL2rseyrwBNzYT2f.WD90UPiW2OEU4t3_cnNoLNGxR797n6MhfaeRjqm9qUdzjombAKqB3b0J5r8KQZlVp7M3DAil1x1ImXzb6p7C_1UPLAdm7WO9GiYEh7L5ehR6UVOvA3_JTHBrVM9yAmYiSWFVs92GEwcQHpveIN1oQ2d7Xusu.6Qa3UUZpsGD8vGJf4JCThipNLX9Cem1Ornmm49czCeKs_kF1oWPMA0_oY7lAs8Alz01hPiFWUGCycWpUjKGlR1It_9047qJMnco6Z9u8sjf.xzLRVuZifCQxzcVi2V29JVjkRvV8AoqkYBjytklS9wAMKfhsPZ_Kn1Q4wvTbJTK2RBHlZsEZZA7.ifdDwO_7TBbuLjq8YYBvYyrnqRKRqNlYBxp._u7tgoTHPqLrcvKMpm50RdWsfMarHZbLKhGP2k3SGEMiRFbU5twbWHQuODwR6on5ISVm2Q8BF0dpQTtN4zk485W.kM1tCRBjAlkIQ0o0RZ7fdazAsiZbSQW_xXSYkXfGYT3CPcw9a6PfL6ytCX17HZnIedE4bec.62UbILGxsEtxUuWe7JUjFO_WpWG5P8d5QUH0kNK31SoMmHkPXXlWljguCIucVQ849gB42wxP6TlIf8vmochDnsVi_ULVCFVjLikaZ5YqqvYdVrrAfxtQFi3XLBBBfG6Nh_fr9ens_zLgMXJJqppDYUXyVZlLOLgGiNQd2L9IT7LYdYabgC3B6YsvfoiAEF18wy7T4gHXmJBNMKu7OiFmQg4J5ifeGi.wuzzmNRnzoN3N0Q0Tmn1vMK9Ko.uOJ2BgKE2t34g3HkFf8E8nQzhOwjKVV828raJasSZ72ArOLap7qioAuRw"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92e54bd67bf73dce';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, "\/authors\/he.wei.1?__cf_chl_rt_tk=DG4Path3kJVrnnuM85oQeI5B2Ev2NSTul7IrXqutCtE-1744320111-1.0.1.1-K3shm3miZs.rilIrzSUq1pD8HmVxtVneQXxNFkoM5lI" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>