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: '92e135765d8a6003',cH: 'NwM_CnVfa6HzaEe3dOewZaLZtIjhtt_Sdo5tuEFfL4E-1744277251-1.2.1.1-PYsoa77q50sANEHHx2f3tRjLP5UYcHLWucuqVYwBBil78brxT_gcUN2RuCcUbr7j',cUPMDTk: "\/?q=rf%3A7340123&__cf_chl_tk=JbJfTM_4j7ujckwsOGiD.._vDhczJrFO3X7Fx4s._TQ-1744277251-1.0.1.1-uZxtfRboBsVOl3b0be9AL88gcDVe1gF2F89KfVMNtHo",cFPWv: 'b',cITimeS: '1744277251',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/?q=rf%3A7340123&__cf_chl_f_tk=JbJfTM_4j7ujckwsOGiD.._vDhczJrFO3X7Fx4s._TQ-1744277251-1.0.1.1-uZxtfRboBsVOl3b0be9AL88gcDVe1gF2F89KfVMNtHo",md: "FdN7TDNYTvKN40AfANr1Mz2KD.lP.kzXUPj7U.RTGiI-1744277251-1.2.1.1-b3tZXMysL71G4haWvMl2Ua_MeGfZjyBx9DbU3Vb9OqMHxAYBMBQFELJt2v4LK5n9BskdIA6ySQ3KGFwNH7FxBYlvVlu4rZKmzXGNfP1sHIXzm6qDO5.gp8hw0dfu71z_j7jgypLmL8zh53zN.Cfuk4qgNvhD58FZDxQinsEe0ACjLXyKNOFFEnGFp08rhYFsck0agKRmkVJLhDOqqX8KyABZ2LiJtFhP9z8Fc8De1Z5ez_myGs9q6lRidqpQKkWmBIu8J2GUvATAlJJwBtboqP_jPgZQvvDwmS9zuWX9P5ZbtUv8jm9lAsYOm1ERipHVKgy1UY_0pPGa1gyPcxup7qkWYy2URu5CLd7v83BLU9w9OvVDA3yMbOgyeEa07wU2QQh4EfdZ48sb0L_bax8zi8RikZ61y9RP.QNuxWHMDyk68zFtRq23wOPm3qnP4ktfrp_UlNg3A3.EI71sq0jv4owCDoUL.2IK3blocXtePbd.jmH4ypbKqcVZcWwtT_8t0p87jiH0wnLu64uJHxi1JjjzlUCiEvAEx60WRJuvxLE5vqqv0XWqwi7K8wHxoWbEjX6E.RBLz0B.yzjS8XsQX0TV_3ug2WvScNBGZ_1stFqMtvsosV1fgyVkQDuc58k6OmCSMC7A0htoPnLsok7lIofiE7s9JQWp0SmDcXdCLebFV4jUjJG5xR.wLy88OIlm257HL1k_FR73RAA893zQ.KDYuxq4nHe1D0om0Xq6KpON8UgyI_4bT7DpUaVd91R9Od8w8qDW.4642baSuDioRAPMrMgei0y2mSMB90XnNy_DoCFzKd4esknqf3Z08IDWNd6q1AUocfxrg.6eSTFRCNa.MlbILjquFkq.vldvWbGaJv_KhuZ26zraeHfeQJaYg.W4Plml4Q94RaoOasj7QMCpViugJXi1P6pHLTSxHTdFQp1q7NuwtvfTuiMg2cqEaRBoh_Q8aMeNpOx2lE6iJbBh932GrlNLBDDbdoOXNks3zDYhh7IFuk9WOicgxrleF54rtnscSlfElYwXEC.ZxI4QVICn9WTpx5z26YoYjt6zfTlpxLZPvXWkzfyj6uQZn8jCDxESlsDBaQ7GEZGA_l42eJGd_wgSZy_eg27Yo9JPyfc1znPI9NSHmN9AQeOTMSXdIouW604f9ZOMlMaiN01r6isqkKbDhUTb6rJLevf0NUIhFJPs6LZ7OX4dh1fg",mdrd: "W4oJTaYZX9MotKqr.Z6jQMRSoXm5kIkUW0kNwM7Yxqg-1744277251-1.2.1.1-.TAUBB74oxn_MQAlA.iIHlIGVROJRWIVmfryL.lX1ub9HmfGMFfr5F4nhcu9iz2mFHjJ3tREr4_994v8QAPRU3Eu_R4MzbfXz3EikuHboIR9.MHB_g5nAhRwqbeT2LY4gcOzud0zj0CUS4EBrq9oU_nWoKq31k7JkmBqNAXGDVXWGR7xr9bFIBTF5YCDwwmHKvxO2nd5OV3SQeaD3aN3PMeb40KWc_KQ7.1tAjjmv1erxNqFzy8AfA0WRiCV_dCgL..fZt7JtrKjsA5FME.x4_zNsw1vh..OrGnUCa0j1NH4Pmb_M31JVPqD3FcDkC5KXIpaApFrWn8pdj.uBbDHlZ3foXEGp7bhP0Z4m.rCBk2pbwh6xW8gloQye_Fq0jkVXVmizNnl_Qsamhe1qRavZW7ni4T4jSafAUC98vHpmtD_QiN8dMZFI.yS6tefQh_BJ.rC8xZUbPjEmSiOlBO04S_1SnzU25Jpsh68YA_du4V8cJeV8wmmftnnQjulfBgaMAFtjlozZoh5qO1Ms2tFEsCoAXVhp33xz8VoA5VeLF3wmqmhGWnMTyGbpbK_TobK5VpF8BuWghJO4mu7UWD6wmSiHGK0yOiEAJo2pnRQdJFHQAHux12HSzgveV5HXuGMuhdLNxKH5wgvXEB7qq.ReAHZt5s1jdRNQFCEe0mJnSeESMG02iMvUH3.yIPVrdHj4Ccc2ma12sDaUtwpQpTEO5pWQNR8199ETsb7SWQrVOL8muIZAYCbaTLBx5YtZCZPTstlrhTkx9F6TstplXNlpM7r_xazQydI2jf7ATfdtwGpW0_hF5ncmPVlfYszSrB1fl1XURRCLwWtHS4SpN5o3EW5fizhyVlWNDW2juxzfE2H1W0qqo.BwrGkRRsec99EwbE_jSzcc30hQyCU697fEj6wFx8X7bW7SEMz_4s1378C027DYmhGP272pqmWqe3PQ5BQjpBVDbeKlZ79l4YruBxj4Pl0zoZq79FinseFft.gv3Qd0DQsRgcS5Z45meR736k57YNk4mERTayT_.n09B3hhP55BZigBd_AXZTUqHM7PIlKSYJF3zT2pl9NSa3nVKIh05JUcDTH0foAxcClwlJKKi00mRu7w5l8xvvJJPg5_QUCv87gUemu66t35RAyi73U5uRzNb0nYG5YwcuiahXzd86pdTpHCmU7XXzNa8rJXD3IIvZvndAFF8x0ttojWpHmhvQrd_e.cOWzVFVrxLZvD25e5jzoGsSkPJS1d3YLYOfe0HkM6l3L8hEgU6NL.0sPdsn3Hkm6BEVgEwhL15otSta6cLDk4zKnTCmELgh4IxYU2sMGLrNHVQPUeCbJ_FsUOY78OLU0Q9X2Js7MdlzgPIetp6uVh_6bezh2oGRR4ggvLvtfaFmtIlZe92lzQUsLpKdAE5gItCqkNmBiUJtvvscLqMk7xsXTRb5S4AcNZyEkxAyetDfpgKv3pW5UTgvtKXASeTgUq42wrFyeAJGv_RsAwMNe3ULxMmViXp77D3BhIlA0tTr0BGtPd0DeNlxY9XjDF1YnJVkw.DYmth5h7RI0cVhWPokfqoxB7KpJS6G6CNKBRRK0LOjbTh86OtROV_J9LoQfNIFsTlBbgNyLIiI5TJ9IgbyWVEdrcR.d4iqTe51LNjGnyHYkaHC6Fxh6._WPWUSycQ.NeyilcrMpAIqZtlll1htFoEemvck0rrGQqDWne4UkI68jNl984Smc78fnIblSyZC52yGY6DmhAIRt_MCkTyFusjHGErLIc3Hj44QDcyDX2FokhsAKrv7yxyQPqFB6lzh5kACDyc5x_GbAm64kC_mLjylQKF2oNepf8dMxvrpSSW1ShF7EB1dcXoV.T6xCR8TQ.6b10jsqAqTtTGwORuHH7pQ8SI0Q3h2ke0QOuifu0n.3Jca8FfblWLR_ErF4bx3IKWWmZUqhuUf44fon77ROrMaXplEz5FIRYaz4Vg62O3lyxW4jfQJ74Ndr7SU0LlXU.N_wzjXhNV5Qsnn6srnJ64K0Xp4ot8HwHFpueWGqIW7XH6XX"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92e135765d8a6003';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, "\/?q=rf%3A7340123&__cf_chl_rt_tk=JbJfTM_4j7ujckwsOGiD.._vDhczJrFO3X7Fx4s._TQ-1744277251-1.0.1.1-uZxtfRboBsVOl3b0be9AL88gcDVe1gF2F89KfVMNtHo" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>