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: '92eb7ee50fd8933e',cH: 'sMNqN_vseN0K7d4nlcu2mfnsjxZCOFlvJ2YLso_tTCU-1744385116-1.2.1.1-wCmmP9JReQDW2JF_S4RyMxSfjrBuraDrqTLqLRviiKCGkXls_5UmYCzWkoXgzSWY',cUPMDTk: "\/7719342?__cf_chl_tk=xE8_Fbk582.Ut6SYTh3Q6_JC2y5CqPrx_jZ3qomfdNo-1744385116-1.0.1.1-CdFucUGEEht3nIgo89fyJ1m0GmKkCE6HLhBizUFV05o",cFPWv: 'b',cITimeS: '1744385116',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/7719342?__cf_chl_f_tk=xE8_Fbk582.Ut6SYTh3Q6_JC2y5CqPrx_jZ3qomfdNo-1744385116-1.0.1.1-CdFucUGEEht3nIgo89fyJ1m0GmKkCE6HLhBizUFV05o",md: "mi7NkAgIEQRMCNYMVyQ5nLQGt8W_oUpiAwyFeY8Ltng-1744385116-1.2.1.1-Cn3OMch13AchQ.ke..oUTRQ1l2aIxzIj0XW2RJ8vq7ngN0bcrI_ZVsk0xpVsFXcopo.pB3Qbc2DSAxVo1Z0tq4PyYxDFNhXdnO7vKaWOUfM1JKE5dIx3qQSa8AdBXE3jJoAvPDqLHDtweE6z1ka_j0oWzaYxcP1yrb9otOH6qgK2mBpaYf7r0DnqJyDLVJLgsqXzrdqs_alUnVI9SwmiGRhAn3FLH06UtSMcfWfBrnVMgxzQsOyFTB4HqRPWT_wHoUc6n0BOJK.SsTTU5YXlC0TEKEyuOltolwuUIAVPLJewqRQ4cXdcuGmwtN1xJa3DA1.q.S1D5C31CymqC1_B12l9pycsKpR_puQJ4n_RMEzjylSgEzUtNljb3rGw1lOQwlB5gvX2hATWHwzSNo53btn8k7gJE58rzThwVudLxNciYa5l_ux.WdNOTIcTQy0ltmdnFhRgAf1MreZb3dUSqPtbB1F9h.YOUEdfpD8pqtMLnEf2t4Pqa9YlHYquJINyCvFqz03APBpo0CNk_PmPcA5dX9sXEamabD5fzTGjsT6V2ygKiG2e3_Wf.AzWxwvMsPB9r9YPLqulFE6OTB_m_RwrDNUhPnCg37G1HRISWeeeVpuWaOQy3TcoI0HqRt.938Gw61MnC4yj_SJavt1R0ZQKdrrBSKHk0.nBUBG4lWIFezK.zjqljygaOCZoZo7QUkSX9KyLxVCkMm_z0repRMhKBnIWoT.gpSbyNfrr2Ll2kFijVRMqUASFbQsfQqpaBDiJT3UNRRP0DlRSIN4ENDJQge5D.zAqRhyUkLN4pxrcpXUhoIXRMuhuqQIRfbfZZN_3WUgpf82oX5zCVTVV70rXOYT_7clTHqn36cPCyiYMENoMS_G7b6rhBxEJ4KldctfFO93NJc3k.QptllJqtKlkPPUphI4C8WTZzQoDXNeVcOuoZSfFsiXKNXI2YrMHSSZ95rCZ695krDiEgoEk10At3dRayDBVVchaEX3Q4Duujm87hm85yfSOai9N9oM9pMjv12_VDZILp214LRIu883i01IlzmZiTB_8_DovjiMYyor3UkUyQHfx5khECgnWnmloAAJ3wQNfQz5.NGEAIjpMVEIy6nqkW0MmoBpDx3cWNu7.YcnaQDLs12.WlUqxgQeNKY9rGeTOwVwoNItYmdD1hAqgkv0_4bO3deH6KBQ",mdrd: "x0cyifFdKykajTl9XgQl9p5Hzv2la7Lv9J7bkztPHZk-1744385116-1.2.1.1-llh76DL9XLICQSeYT567QpI9T.XFFQ7GJSyv06QnG_EuPBxEDjb0CZr0RP7TarrwZUzwYTHqIhBh0kmIBN5xDi2AECpqoW1XkKnCOyQ6Hu5e933dG3V3tsUbikJz5gDMcCbJvOBHJL3wuat.hxcjbU2NNXp.oTZKvWvnt3.Wk1fRVAm5V5cPkYIVxxtEVg57zz2EGpumBZNYfspHgwccalj0yEAFSAojha2dcN.OMUWizt7BBpjgkM6dCXsGS8NlAN8kyaTCrf.5Jkyur_V84otmBEbDWiGl11uA4ahV4jRaBcWBmSdhwzfS4P9xx7TEVkvzpGgbUD8W2WxoUr3sLxrGQVGJfPjdh0j1TM64jUIHI99gWhxBJlOYlY1RPLo.R5SWBA1Xowv1hvQwvOyBDGvNDodrA58vwuwwc3Vvhq4alqQOURus.nHyBAeoZVIgS6Wkq.iu5vGNGltWaRnIa35kX_NJKzDlQ1pTnkPbKL9Qfo5ZjF2n2fH.rz59TE4RiBR2HFRKY3j0.RoKHq0g0n1rGS78Zk92J_jrfm_xsY3TVnsR29FyyqhUsEnib7xLH9SHjHjOOd_.qbRwqGdiel2Mm7yf8U0TluW2K.IEx5wRwpqC7tdRrrKtMWOfAlDYYOtPwgGYOS_YH1cpcQZ3QVdBZo8nuU.xadOv09nB8.4.UYQttIeopZAgWRDOLT2d9g1suRtPQvK1z6FIJptiEVvncQ76WZWY5gh_Lpf6FTM.xSZskGNNT0r6WeQE0iVKCM4G6pyMhCga_I6XKwhTD.lZJg_G.wlglxi7p7pQlKl8Xev351aaEMaaIic0nsgw459Yy1YPCEFSqs5aCyhwFIRwXDvw74Q1GowekNpmBRaCTQ2_zgAi1hEfOGny2eXXJtCMoWdajGazQue5gFpyMa1JN_Eu8qKkBAVR7zT2Ruw75fHEyWYNyWX0J_.bV1RfmT5PO9SqbAMJVioQY3xLuZ9h72kYz.SlCZjBAhiPjf3Ki7bpzAD2.zis4XkolO8lawyEtKUfMHXDQy7j05T3sSltCmtyuVWENZSw6VQ1DMu5vV.LZq4Km6l.CH6PJm8bqKo914H9_bpykzujYYwB.kK.ZXogkJm.W08Pc2TOg1vToFcnSBGFczA71sNbrHfwmPkv3AC1f.a7pLHE0cWbxw0B6qt3hg5y2n_ZnqH0hHGSDBbbpgh60wQeqCZ4MakYrZVsLvDffULkZVpkrZb.llq23JPBbVOq4kGBCGW4dBNKENbAjgTSOEHKzx9mmaue2QwYWlUActD1EBihdrqxAfS474zgcpXscY8TYefu5oOE8ltQH_vyl0WJfcVUewxOTIEIuYTLGmImzOHJR8TNOHireZCvfuKR1rxT1sHIIQaSmXYCSZHuWnd4K2aHuE6TkENP_WKNFAvTWhUejOgqTRXHF.z39MAMwhBViwqViZ2p5_OzbfyqvOAAePowkBBiTfof36jMw0fYRDf8w6FYfSW5nzhD_jk38O63cR6TGWYC4G.FYNyjl8Wj3SwVHfD5IwffHFjFS.EeD1gTSa..7VaFZ1z6JLF38_fM9bMKNt8FuBHvEF8KNLuc9s9QdsVSdMa3THFtzoBx6Nrns0Lxoj73qe0S.oKIEkp3PKM91n4..NMO_UpUvUUY8xGUcc9tenfJN6b2Q3XSZ.cqwNK4spjVNu3yT.xoYOXbltx_kGgDPrqL7.9_2iKg1967yN5u4XrLbff2hFyi_lTDSBCS7zQuJOZu87JnVv51cQlF_Dbyx3DW8Ks8W88WIgfQu2oRNe1jgZf1rCl8QWQTeCWYRq2V.AOQHZonqHhjugn78Bk2eD50odMSWkOnRKiIjF3lJY_SPiPtkXXTDJROLes7rrlcA_x0zE_01G9kBVruZICOLe2dJ7SxJXi17x1raHsM.gZobRw6WOBsQWD5DEJKetzCzLNcm14BH8M0kTtSxU0lW9dj76uGymD_ogeIpyhRMu9Si8lXdhiTen4rQgdhUIccFkmMWLoouLTLfuXUhFviT1s4KbuqtaJuNsEt2AIh"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92eb7ee50fd8933e';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, "\/7719342?__cf_chl_rt_tk=xE8_Fbk582.Ut6SYTh3Q6_JC2y5CqPrx_jZ3qomfdNo-1744385116-1.0.1.1-CdFucUGEEht3nIgo89fyJ1m0GmKkCE6HLhBizUFV05o" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>