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: '92d574a6a8586014',cH: 'VFTyCsvMunhlu2jeaWt.sf6ueCwUhKwSzq.zFfivIwA-1744154010-1.2.1.1-tMdMqFMcZaf7d1pWWgUolr3BMwPf5ja3KjSoNj1xfGKCASkrIOw4Uw9Qmzw54G7_',cUPMDTk: "\/1272.94018?__cf_chl_tk=CjNXrGqCYd9gE7m0SuP2UA1SKR9qH5KASgCsU..EW.Y-1744154010-1.0.1.1-uYD8CGMXf3iK4yHp8LauwxnuyvFu1OjnZWgU.iJOSgU",cFPWv: 'g',cITimeS: '1744154010',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1272.94018?__cf_chl_f_tk=CjNXrGqCYd9gE7m0SuP2UA1SKR9qH5KASgCsU..EW.Y-1744154010-1.0.1.1-uYD8CGMXf3iK4yHp8LauwxnuyvFu1OjnZWgU.iJOSgU",md: "A8gWGMBWf6EeCaB3D0qzMevfufkvFQRvnOBZVeivsmI-1744154010-1.2.1.1-52G_Qb9d9BerMn6_PkasIUiuUomHtVn.a29uhXtnOHZyPesd11lBZBgFfPjGpQtT7uqcuF0TG0B4bXC00IOu27AwRMv_Hex7pk3Uf0Gkgpa0Yp2ciMK69a55yu2wDlFlufjIBUQhwa_Nrc2WaW.vEcpMM1UlckkIY7OKGJIP_hjwJFas1jgAZgJrSgLMn32TuewqHP7ojozqnCnk4gtiasZLXMmE.2ADOna8P3FX.wGdxEw.C7JE_OJ9p89eYWMSj.VF.wN5ppHu0oNOzidxZj4saw98_OI.4BFc0IuEnP1LI3JyrABDigoI3qV63urmlGdApRSWn8viuiM6qoTDnGAj3PFVMpxUMNBVeIHpHbgl1CnWLPMF8ADMWCmR_Sq6fLbtBVrvUfsz8fUp7YwbO6Gq7yNYcjZYuijQOHutK1V5kskSRhWD.X.z6uTtGvR0.FGS7TVRBEBx8YQcgfZiNFlBiCM5iSRW10AVh6suLwUbbMDbBLINBWDTXMrSElxtVb7F1QWwtg9WIXNnAu4IrNnHHhbDT.MAY1VG_.b2HZWFGckwzIk4fT_xfhzYet57is.WXX8DKXH33bdNrnHEgtLS6zNtuSmbuYY6RPK0AqqO4f8vAArBGRgCtebnWHJz8fVBDP2mDU8FC4glaYsD1ej2uq5WbTUcgAw.i6q.TX3KN1hBrEOSRpWYRNNhL7dj9_jZF5XHDuQl.1hqqz1am8CH8q9A_q.jT1vDJOwKEReNy9iTabpV4FJRvzcEV4gc73jVbPrEbhgEW9.Mmufd6lJ9qR3iDroLC880A1HxEQLbVooEg_kOTq1VLubjUkN_QAldAktyRVVZ2BjZif5rFF1FM9zz1fkG.1B8T_ZCWFoeRhV3stWxyxG5zXUYhF.XBGl0IRrIktxkKU_ABvexUM1EV4S3R2MXfDU_1kgzl7FDC9EunB0LI0.YlLPHHq2wmogpLIP18R_n91.EgnsMj9K1JOsCucukmg_b8.ij_im3adevXQEXqr6Ei0FHqjUJe_uqbAPZENl4f6zjlL9onF5.OVa4S03foLrZUe9Y2m22jfeFn12OzurMYrW9536khqsUQi7OuF5WiP5v7SlYfF43nNV1V6gb9u3puI35ahq0vajWdJOkpy9KsWSTsadcnWqMwlQxPuyfU2r4CqDsyi3JZPIIVGU9ycA4Zz4H3K6DuPl5HWas6I4.WzlGSCI3",mdrd: "OMpZ2deG28YLuaADiUw.4SQJgIOhHQp3rOR_LPNyCzY-1744154010-1.2.1.1-4OPT_uCPkYjut9l.bKxvCgrASuozb_7Fk9a4eFPjEYHvTcK_1F3rLHLwwLTV6UspwiBoc3s8O1eSD4DQOQe5pRNxTIVdmkoIMEFa0kA24bsIMDAol5uZAabBearlzFFOvqw0Kp6p1StLU4HYYsyJj207gYl6coz2hP0FpTH2.JSy5wy9PF9G3p6ZfEA8cNjrhfah7KoVETFgseYISqxvHNOmrG0UX2FADujEejJ9A_qsw74ZA.tnr.eeRZPWbv_U9YHxy7EgYDNux6GxrROvtK0nkh02uetD83xQzMS.nwG9yrq2.E9fmwjztQWehRxCsvPR3T0jlPIBLbS7lgUJzU5jnrurzqEvfNMMt4jgyQWaQ67Eah1jdQYmViOTCI31TXyxsfYSMgmrPswtegc3IIpOaB185Wv6P.bwCE7vAcVmIUUPBuegDyaYiIEa3SyYFEMdW2myXPF3.IjYjrU3sl_mFg_jBx2UK4L4gu.sg.SZRe2k1.zGRvWDIcQ8aY5i3YlLrpFMsWiHAuMLvYKtIA.OV1gBPI.DQeLOeKM_WZxEn9XRROiwysnhxaJt7g3NdsVVrttCo4Ugizc6EVcK677F4Bhvo4KDCxoe0BHGn4jiJO.cdH8STnfZ6vc7dwh1wsl7f9Z.0PLCMr8TLdICbdf3nT57CnuAqqAv4HM42fNESS1hTkjtHNYGaOTJiL145pt7ULmaxDwx0yY0wE8Cn1Q391_6tK81Yj90IIK6XMCq3qb1tquYIsbBz_T8skS3UXbBwpZTIg2VQWFpoqmCtH5ENfleeq.nMVqH9UB2gPrdgQ3qBvn534HrAMzlGTAbsUOFKHFeba6aX8rKO0_fTi_wfgaxNXcbEKuchDnsnT4U9eJmmSH.8vhg17.U33cRzZvu9AYjCq74ys1EWOFnNX4X5kX62v.F1TrVPCM2PHNNz0czsPqiOFT6otodpqmGRG4eL16upSeOT7YcLT7CSN5fWu9H5erNNMG5.Ca3vAzzi4FgYzLXupof92Rcf8qJpK1FUdH3vePulQJQNyk4JgBBJ9ux72RszGT4B1KihUKaBW3xE5iGhN5hDsFYHhyztZX9Bfbg3KZrQ1QWQ97JyWZuhatRga_fefhJN_XOzwEVAaB4UfC1UPQYmR57KWYcd2t_hNQfiRzktdxq9MaW3cnWppyA7POy0uF.MrJ.k5mxFmj6R5bGohQjNwOKisRip3_vr9R7odmrdK3OAVGUSuaN5.BHoD3efwjOhfMtK3HcwfHtEmcWgv04JCGPPvleHgy6MjrbI9pH5MRqAQBDEdLyEg7mHNGCPIRs7ZBntzMFDz63PVG_9bqib9SMHY7VYFuri5WLoALeiL64oYNhOg0PZt7RoQ9pHN6kbdvHMBkwTBw8PaRbgAddNRKwFSQXYYLRTtrdwjKdptNkXfhfncuLMmpQlDQ.kABs7J1XIhp7jvisHsqABYtVWRBbJ9ciEIO7FJ6BB6nzXEGheQdgY8MHoDDqczh_ZeFNPAAValFrE3AsvIPv1kar00beUbrSF5ccZp6js0KoiSID.qdoMAr6qGkP.pYmmMG8fkFsN7iM5WX3hOAmhodMne6ubuz2Wuf176GrZxB9SvO1YWcogNcNRapdsHPMEqzRdBMxN9pEE4gB7UEe6VjM62prtaIt34kX2rMruCXekllqaFm_r6WbMf2LrQ.Ox5JU2pvl5fS4n85AYjimOXmsm5zcbzPpPQcbU0yIUEVqA8GVWjOFDNYNXbvVPaPzjo9PY8cxa4jCX6tGgvBzATPbgJMyb5g6P7J7lDboCsT_KnXcbstXuuJOyWEd.R_Qdy9dP8PrhssblFx5Mck728RXA6fc8AJaEAcyLX9dzhiYHN4x6rejFrosLFnk709bOKqSprrmOL6gkPgASJE6t.KLk3xhdw7.y2chYzLqLn9NDVNSPcaD8ouO3GynxeLSKcKxg2ciNRDTAr9UcoxZY9WDuebmi.5Isiumx8kau85yUVyqEi95siXOaQp_LDxwh7stYRZdych9fQ5VHxnC.pf.XU3ioB5A"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d574a6a8586014';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, "\/1272.94018?__cf_chl_rt_tk=CjNXrGqCYd9gE7m0SuP2UA1SKR9qH5KASgCsU..EW.Y-1744154010-1.0.1.1-uYD8CGMXf3iK4yHp8LauwxnuyvFu1OjnZWgU.iJOSgU" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>