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: '92dfa34c4c0d89b8',cH: '1_mnk7cH_qkwoLHhuU3f3WpE.nshUoHpRZqKe3UhrZg-1744260778-1.2.1.1-ymrNdxSvSpwYPOmAiQ2qffSoDpVIOzctI9510LGeAR59URI5RdwwWVst9TwRupEL',cUPMDTk: "\/0869.76003?__cf_chl_tk=o3Jpg_nsvlafnRgKh60BP8RdDRjLCeusn4VUn_brT8Y-1744260778-1.0.1.1-LJoi0l5NQbuyC15NnTGObDuH4TtaAAcoOeKQfyKuMFc",cFPWv: 'b',cITimeS: '1744260778',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/0869.76003?__cf_chl_f_tk=o3Jpg_nsvlafnRgKh60BP8RdDRjLCeusn4VUn_brT8Y-1744260778-1.0.1.1-LJoi0l5NQbuyC15NnTGObDuH4TtaAAcoOeKQfyKuMFc",md: "k3ZlsMo_6pTNcE._imJBUyI6icWijNJnpc3Ajx3K2xg-1744260778-1.2.1.1-yOe808r_197CpNn3Jl.tVVLVphQhExcBfXxZPZHV_Bmb7e5DzffnfdDMRvjXXBHPldiTq0QXbrz9WOrd_pDM8tWXC1.N0BmbCIA.kUOMMvk4yLp1aq8JIXlS1um3MaHkApbmZ0EWWKNAWGiUC16LF2CZuEuVNqPAumu8PChbCNtML1xndKBjadBlXOZ78WlaHsXl9fkUQOpWvQsqtOFoSJ8y.fm6pC6G8EpeR_7LrqOHrbrUzF5WE048MCtiM2LmjsPLH3epkuWhm0UJ1Jcemd3dCd35QTTKYEB1eUz4bQs8y1MfuNoEZUsvm6PzT6Lumh8Ii.HTmItrwG5oChUD6ylbg5CTefVJXnTl_9mR3Rl0lbfBBVWhaGlDc0LtIXjmSLwWXzaVIY04pm57ccd1saSDxYE2LIRMlh33d4cQZoIdIRNdVQluV3R3jB.EqGVSCsr9cwVGJVAA9LpDTxWJIwQJBxlCRfITkHrbLoGSOgAncVyTQ3FnDLzDg1n4D9Vl17TathPiLasoFdCBxIEiDr10T3gYECPFs.NWW_JZsIwiVybTwT0hTY6_olYwzhTnzX.sajxlDho0gfA6oIItHQDHp.GjzLJdtK51y9NWnWqA5Kbdvk.k3H__lG_ZJ1tR6e8nTacdyjkZuEVx23Xi.QtmSE5TNihm6LVePYG_Jig8VgvFJMLDpAAbTAPiIDa8aFz2NjQ2fJKaNKdjDDEOkRK_gkvaVadQhOTtMT7cWxbwoLi8qBNNEBqHLpVajK.ij92LODDZujt7Y87.b_ZDiedOcAg1sepcaRorNPtM5pJ.2nrvTfxyVLx0pFDl6BFcm_cfa4kuOqQJMQXW.AHJYk2OjaJZEryW1v7Cny32lqvZVHP4TSS_qKveUpUlNETQWPR8YNKYGG_4IBqK.mCDiwR_cMuLfPQOvhT_WnCUxVh1yZG1MyQbmhBiiFr9.PecjmI18lMcCpnqiSzjTjdg0tFD.6j7nLZHtevCRzv1Det4swC0AfIP_VFHjreiUEAik2RDInBq.P9Cey1_czSZ2ZoinVYFA9sWAIpXcLxkDwC4XQNtrfqWiBoFlsJQMl9VN3YdJCGONh3RzcAYASi_5ng_z3wjBLdUboGG5zkWflgFdkz4qvdAxymIr6IH3pCBQbFDyp588_BF0yekQkC31fDNI6gb.hhXuTfmIiHZ9pto4bzMe7ITT5JJ3Kql_zOq",mdrd: "EO2HLdylAVEXX965s5JbAeow6KGsQxpObTukwjRNOUo-1744260778-1.2.1.1-d5A5u3OdJuw4whjjz1.1oU4.VmCpdpsmEeImO77L2yw9thHhGE7cp9omYcGLYK6LpCrB89Ny7YJqW6JVwkqbpvuFLN3TiALwlv1KWaoGZSA_qvEZoB2WFJunT9gAeiZci5A4NgcU_gLjs7SZpRXpxLk_nGL82kEf_pev7p4aNNrKKtNVn3.Pgf0GkJrjPkz9LbGeOK0HCZUd5kdKm0CneFIGV3AZqJVQbHvAcNoWDk7KtBWcNAlGAw1VKDn3E3vVGYHFdR70hMTNLBN85LKtQakkXgooc75ZNxqyK9fEDSV1DcAqUu.XTpSO0mHnCSeyQoVbxVXmbcewSWkkx15qcC6iQrz9hXZ86BbJZsSLj2LO7kSz5x6ePS8wxjNo6p6l2uW.XWWVK6nM63hgiv4uOpt2WIOt7lQWutQFwJVvjSzCoY02S9gnUw_PymRF8v0WZmZOWIuCUxBm2.yQNiTPEdwjdL_ik.snbkzffjCZ4ZebcDAlhbG9Li71gtEEtSYL0OGDKweAhg2DnJwXqMtzNRNVZVV2LDI.cmJC9iHJhkj9AUcuvHdNszYkAP4yR4cEys2T7gOxnm9RKwbKZCUKbMuysJo7MKf1jdMp.BZdt3EyctVKvpq2MRKHPOUF.dZgT2NZaekClLJoeiFxUp_WvH8QhMq.D7kJ0WX38KJMp8kAllsIeQn1qqqz9BNuEa3ajAaeDjnUTyB77SlHb6qyYLzBtrXDueLT9tOmiA5vM599SzZ61X2elFcKSTxHNv4C7yjAr2IDqZSa24hPbQsWnVrsItvygFuWRcqzShZDcPlMKvUkZetKuB30j0X9vJi1lUuODyiwOzByD5lbVWXj92_Y7wKJorGnO7GycY4ZAbF4LsF8D.B9ATUTA5AUtfbSgeQzm5woZzj95wDdwHG1hGuUoETPBSuYxmVLOTBJST_WjEl_9xRiwPzxz6vV0cPpTzW7BYgr.4dJamOQvmO.QNYuZS5YHcvpyJh2vqY5l3oJ.ixrAK4R0doilpKfysqUEomSZDh8.n9qD22lI0YDUEF6lYLHIJpwN4EJsujmioF.vTozjIiyY89JFTUftvB56e91uHgFIWpFaCwDSogdA.IoH_StF1PztZWr.7dP2km9hXAXnQyVr51yz7r8uTe0CtgHgM8VGtn3cKTAnnKCQFL6dYE7rGwNi1.jGX4ZhouSo3pgqwufRV.Y40zLVyh2fu8t65kz765mtJqvp_retQSY5FBGA0UwBxS_3o4pWXoyFsXyRmj5OcyycHhOm4P758CiurtARRxwZFMu_diLV9MuQe4j.eQY1ho3xVUuUUnjrqL.qqELH71AGiNUMwj0zsbmiIqOg24VQDoi7zvWhbdA1lWIFfWDqmgh01aNIzZnyjRWOZChVu5i42wdHWgFxgGUpaS0XP9gevnBgzi1MMcR.eVNl11CHgLa8yS8NVXkf_q4tfkVJPw6ps751hkDgJE815WvS579g4LlZRWo9AFXqgFq3xCF2_TkGzPgw_61psWSsZb.bOK7JWyEKoopfef02mkt_odJgyrlBga9GptjSGmCFMGEY8JeECeqB6qSIDK62fLRAWZKdo3wIuqwfHuWORnslcLocEGWQQPMNMnrS5nEk8N8SzocEZ4A0MA_HL0n.uqMO4xP8wz5Hzs7dqUjlvoL8ttKwbM3A7kstoH4l_0yo3LEDa7jnGQ5800wVhkhdvIhPd5BeLuj1i3ue98KzI1WYsGEIQJCNMwZTHAYUn4rz4J4bwM_yCqc6o1pxhHc3Ma2x.2mI7Itneka7v69vtV4m7j8L3ywzNJ.WPCqHiXkieSwXACEeIlmDMsQbGY5jqJg7TxCryxkRsIL2rwP9YOt6X6AqNkg.DYc9rCod3qSr4Zv98nTl4PtcztbnJ3WFF2kA8j4DJH5kHFhlFgEjQ7vaAETCCPSTAqyeYAPOr9clS_4XbZtprxJHSjp2Does2K8ghO_lfUZ65dj.HJDfzS35M9XBuWXTIOPywcqv.yGMrGS9ym7OvF7uUg.YtfOjeTEo_TMNAHEJIhkZIIBQwi34TvF_DCanJKLcQ"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92dfa34c4c0d89b8';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, "\/0869.76003?__cf_chl_rt_tk=o3Jpg_nsvlafnRgKh60BP8RdDRjLCeusn4VUn_brT8Y-1744260778-1.0.1.1-LJoi0l5NQbuyC15NnTGObDuH4TtaAAcoOeKQfyKuMFc" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>