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: '92dc7525ad8b87a5',cH: 'ejMay95mhn5qSDf4Uab_nE31E95pLF6HcKtV4oo9txc-1744227431-1.2.1.1-JRUE7U_BXsBfW2Aw2smfewE_Zbf6wD9_tdS4Sj1_1vCadcMVq4iaqJrMbDIgBC9K',cUPMDTk: "\/authors\/cao.hui?__cf_chl_tk=fKj4_SW2zbDgoSSeYj2vM7qclnK5fXXJ8ioI3rrzLrU-1744227431-1.0.1.1-NiwR2PbO5oH72SLndO.PC9gdeya0x9hz4GPcR2QtwB4",cFPWv: 'b',cITimeS: '1744227431',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/authors\/cao.hui?__cf_chl_f_tk=fKj4_SW2zbDgoSSeYj2vM7qclnK5fXXJ8ioI3rrzLrU-1744227431-1.0.1.1-NiwR2PbO5oH72SLndO.PC9gdeya0x9hz4GPcR2QtwB4",md: "DdkRR9kHL15bIijF4uAPz3HP8Evmogm.meO8p5CjAdo-1744227431-1.2.1.1-lCYY6w9tKXn1QGvD9T6t3QDvcDVxrctnWw8BTi_o0w9OoYLWAxaW4NtyCZqq36A0lp0uzCIiy26aU8CCKB2I.p.Gr.ZrVKKbvWQ90OlKGqkDFVQksE7B2eEx7Ar6vRtz0P2ck0qBTHo7_TCaSjPUQBWpQz5tk4rjdTQMKpMBGDfwSgnlHhfyTVQFsJ6Ztsg.Od7uUO7y_9T.d9yoBFpbwZA2cSVBBPv.SDdITYiYoGY5DDGugoo0r9OjNAzRGPydP0PyhocmyzRFua6VAhKszoM3QGzMuBFcVl6FSCTUiASXoio4in9Cn2ekM1ixq6uvPCg4ZJcKIW7tp0tMwd.X_ZXsulp5CryndNAaITE0plsHiBkaPV5bXMSFBPLWuLmpFDV2r34et4HosiywNYcstbIhF.bqKuo6PObULdyduVZZIeqJd2owfyXSnoqBF3swtZT0ax.iNc7ECwjd0Cd4_8bl0wAmJuJwPzGLJClESv768IqvCeoz3WP3TGlTWAs_mPoky6fmPHZqbXTQ4zWBdMnQbbKYXQesWvQ3tLMCny6DHleUnFwhRkPaBhZ4V9Zqdqz6bjyr7pily2lbkCl.N2tCG5iiYouQuL.mFwiQj7ifPr9q_JnKrvMysWq1sifl5P9hUOOOKcPXZwaaNX6TUC6Os0PnXTa_npmDUQgOk5aNQjUm9v7_R2T0LDnPdQ5SLMqRgcWaFgGLwVVbFhDMu.pBDfn5nBFv7xJ0lUu0pap2T7bFR6vVKZDA5rcLGvzjjedEaLNmRgbg7xnE0bjavu0NQADVfzJQjd2xbr6uQI0F0lKF1i62MJpjk6dQU0tbGaJwFjVnOtP0awYti4582rR2eM8czU6soAaFbFTH08fpP9uJlcYFeULO8AhbyGbvVow_n6JXwUtZoW3oRQ4NRUkwG9CcYZjglg1dgleSJ8YbmWD4CFGyQgUjUVhd.UWFQgJuBNzV5pcpF0rmBFRsJ33Z1S8J44BDDHhhU8QYRFcL_9eslN_BBwrZAP6k0BSxNrpMVnZLBzCnwYQfcb849.Lsx7cTR4wcY1_E6_FEPshNCHHMgOV7B1JU8BGcZFvpj427fvfoIDfYIc.FNB5XO0Uqc.SeymRGHYHXWZDVBxZgJHUymeUQAhYGQsUuw8WfOUY3pU9Q1Uy65fSwZ3qxXbbiToN9dBaukbUoGM4JAAZV0JdCKBYkwBlAvIiy9imH",mdrd: "2oUCY0Oy36a6Xi4v8I68Ack7zrKhHLocmarJFRb9dwY-1744227431-1.2.1.1-dWYw5Blc7s30V0n0ALTfb1I2UJD4Hbc_eAkpi88Qgx5_9j3Yo1vhgxgQr6k.ogNQVWJCKyDtN0DBjSkpHri7EkGxiogbpkkHuk1Qfy49Tkj6egihnfGvJAzmAuW_33w7RurCsBVGey8EWh5WDVd.B74zm6sKAFYXghG9bL3FVGBPLjIb1bapK64Se0bV7zididnIaxSEGNNPyi7P4_za_4dmS.wCX9juU7DSrx9i1.UpCPrtv5wTDgtSocPqW1hf4fWcCL5YreOFPq09o.qrVRXWGbdyvEozy3rJOiNY95qoG81QUJkqiQ8uPLVPk4njvgF6MS18jIHqIpYvoI2F1yo81iJu_3JFVWELQfkegMzwBGrj444DmzMIiHd03eS5WispcWsyzsuPxzJZFs3jex4dyIpY12nr0JflKvAwlbUNfIF27L6xrvA2UCgf26FL.8LpyLHrc1PQeXK1EE4Gj6EFroybP66bbO6TE0pN2AJrZNbMjhiJOdrR9FrROuRgQuaRRXiSOPxClIt_lMVrXFpoIpU6V4TN7yElL3Jfea6roVWL1QdkLXFxNAtz9AFlIdQHtQztR1LFwc6EUOwPeNkczdG8EoacPaJwzsRqNAaRWAZ33zI79YCl4gfFDz3vEdIcniI3BN.F6EPAd7u.M7gaBOCZwjE6NcHh0NzoXkl0ZQtSzT8SVMcXD3LRXCd2WRKjC6pUiSbSLsyuqJqBZSr37keb9cVks9RfK16V5p9I7atpoOtUvKkFYfzIwLj7AWcWYml0b8XrBo5G3ctudAyRqXDkn4d_IgnKgTN8iXHJXd045_ke8QnZm8iUgg1odRcrThFVOq5cBw_i4ljriTNaY7NLkQKX1dPGl4WEMZgTNlj6elalDbS9L_Slkx4vsHrOHp2oLOolExgoYnVAoOobIHW7Y89k4yL984iM21UDzq_GuYLKHh_ygO.2K6YDro4LvaPTga.qIjvoQSXZ_wmqFKwzLGtqr3yA6No897voT1GPx7UTeH0ebdQrqPsnWZa6c73VTnGN1eAr5nRVEfLKluMVSlMmZx9ygQ4dwyreXn6E3kvZiOXNBmOmwXYwEPzO994pfyzPPuuz7TDlmD_IOTayTmuR6IOHBJr6FiQjSfYNCFJRylsepiD7Q4HLnZarOMfhVhbgT0yGWvxGouJxKPM2BF8ehsve2BNFKNA9HdT0rUUhceH0tGaorZuuJBlBYhop9f29c0Vl9ldltLtdlr2XI0rhz8f3925OILayqqUGFeb3qcGFtaCD9nJ5_R.oFv_M4g2iF2nBnW1pWtSamch85voXHoOcrQdDMsVtOuwVPO3Px6IlhtCKbmKtgPQdJqCUBrp5dyMy7lNJwwA.N1Q4IV9.YQYRGu_V8FR93fkjlShVV5Kpl8fo5l91pxQWVoBpxjjOZ3sB3jjnpTTBtLF3nZoVvRE_Wuv0Ghtd2RFdIgfIXN2ATZSYAjp_XuQPnLiDygE.g2OLnSqkwalXgPgrHDTJwsjWS9YzY4bEDHFwdcAksq4UimOFjb7popt8fyqzewM3IzUVujdnnaj2jXqui6GdBAx6tyz6oSioGipaKSmtu3UqWc419_Rhff1HYY6DFA.PreEVB9if2nVp1l_wYsl.H9fEo9t_9m6BQ9_HVGDCNXeDzFaSWSEghAQf2HDeMQ1NXqL6HgRD9cuYs8QyeMpJXF1_LkO6HY6T.jJ_7Jyt2gsSn0oOYJE0OzPwQQf1kpyBXHqR0JkfWyF05OytUXdkQklKnwRJ7RPLR9ws45C3K5Iq6CLbt45wAd2ppwp0mo0.VXNTxBI5JD2XGAywqaB1X1Po.7kHjy0PFRgVQWafFFIIBFS2R53z.h8pMzO5QXp5Tp_oWeEX9F6_J2oxmtN8GrO92js6G21PCgqZZ4bunxj.bMgmsaLHYVxeV2A..TBP5llBZt1m4a745kzYOGf5he5H3g6NnYHOo9U4cSyXtai63KhoU_YuzwGH5zMde5jNG8a_jy36hLKe0qMmnJKC6ASUoYeHyrfy2R1aXmDeNXpQasB9A_aq"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92dc7525ad8b87a5';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\/cao.hui?__cf_chl_rt_tk=fKj4_SW2zbDgoSSeYj2vM7qclnK5fXXJ8ioI3rrzLrU-1744227431-1.0.1.1-NiwR2PbO5oH72SLndO.PC9gdeya0x9hz4GPcR2QtwB4" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>