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: '92dadb927a1640b4',cH: 'lPzYnDTcHU3FvPvMr3J9E0lRqvEnVuTpVKWce17GmkI-1744210655-1.2.1.1-rJbBoASrCYB8rJAQBJysmhd.ajgkCft.xA_cEhiusSPUU0etU6OVcdUAWyvM3oD7',cUPMDTk: "\/1063.68099?__cf_chl_tk=DbULajd4DIjBzQ3nobFIBjPEZ2m8cXXdKzUxC6gJvok-1744210655-1.0.1.1-nP4IzZxr2FiFo06zEGYRfwGaDA3EHj0p2GIK.6OQl4U",cFPWv: 'g',cITimeS: '1744210655',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1063.68099?__cf_chl_f_tk=DbULajd4DIjBzQ3nobFIBjPEZ2m8cXXdKzUxC6gJvok-1744210655-1.0.1.1-nP4IzZxr2FiFo06zEGYRfwGaDA3EHj0p2GIK.6OQl4U",md: "4lyoJ7YE2lXBrWvClVyJzGiyGlXhts0pwVsQt9T33N4-1744210655-1.2.1.1-1ekLrU4TUIaykeOIyplso_WOvZxDjuxqSu9vvQo.XZdaLvQC_szxv.m4sor0Uiwnv4Qaa52WaPcnsCPG5c.N6BGYsGD7PnHccoNoC_EQjOvxoBkueM..rTmGSApbR1hdhmPE4GmQHIdSssbzYUbYgAG4jmQPsAOOLtTbpgAUv298VYgsE9m.XeMUQx4swifm_YsqW.jOt.EGStC4cgEb4Vf3NXvTsa6zZNk.JoELGn0gkkVshzwId8nxBbEFBnWTmL2krUXed0SkZBWkM4lP5aDW2Y_kWMcvlF3x8PGHjwG9faRPi.sjImZg_4dj4X8pN0DKG4YUaz6wxfUA1tiO.sCAPvFDRnMINd9Am1v.OZCKeV8JYy_4w.87_Q4V5XNrDdqvSNLO7iwBMG.gLKxPjZsy46dfIl99TtwKbfqy4gnjV2CE76gn3QIFwqsHDYpnnYgY0r7B.MGWxPbp_BXR2x.tUKNPN7f_QkdHHmV56lOfVxg.Uf_3AMpMJYsKRt90I95l7BJa27YfWmZrRqkYBju.Yk4CjpEHLHGvUwD_58PGUwFaql7vWQJARUABhybOCFEp0ciF9jE6XOTewasFtB3Zs._TzL5BT8FHAXPubU88s_eBN.BvYn1niX95sd37hlVsGn4aSGvrIoVu2JydL0pSMbHkLgYSAlgkZL8A08_jneVSRFjuzdRnTjBzgd_vSf1Jqs1djkwMjl9QS1cgzt.Og1jw6CsBQUjFWprWP2nQteyEdINeNc3EHT.ce5IYnm4dD.MdEvwXWumIphv.CCXcuJXtG4jRsGUfBrnpalqAzd07nRDIZeVXzMWkgOoV6UmD7BEp7yIXJL7gvsJ6W4GYfjrjq_JldqysAqJH7lsbFJ2lnQMfj8mCY2lLozfFvpl9MCiptkl9hv9HhfyoUqgL4U4mDiQqvZaF1x5S7VfTl_XdiX66ucFK..4T3FsPhH0sFKdED1xL3PbrdzWpEzI4Rl7Lvx7XlqsUGyvHj1tkIQbuu74pjd97EwCeyNzRd7el1ESyG5ye4paUhJgszhiNs8e.0Mk6YdjBsoqcjJsfssgtZOZ9GnuiKGamrqXS2o4nv8rWvK7MTw4gTywlVmPKzdeojJb4KcDrvgsiYn5QfC7y6K38YK4DBGQXhFl65bMMSnojyRqtpDlNduC7ZMM4mVTqKCWmWzTOeF6OPZEKQlYuqQemafW_BK.XrMsy",mdrd: "ZYNDxr54qfOgYnnfZz0lmkkY4nLGMABNzfIP197lkrM-1744210655-1.2.1.1-oSVHm_wS6xf9zPqeVJME5H_7xOPduB1f2gvjjoX6NjRfiKTkmJ3gb9KzBLD_LhwJZE6JIVXmj_vbfaKEFGM56kaaq8NRpCh_Sg8PV93a30MdJjVwgzC1KFul3owpO1YIELuvBHLMHmV3Fb8EIrcGQmy8o8e_2fLJErpufRa6jZI5SeXhQJso58SkViLIZCSIj3yZcIvFEJYnqWLQ4mdbUnUAcuNwnSlBdmvieklaMLdylO.ZST82FYVRFcza3SObT1ED.ogpB3ESyU_ETMlxDsG2U61i3DPeWr.9bNZxO3fO36BOlnn4cfzQ1JaRBkdwJgvtQdux5v0QDb.59rvXuqXpeaK_i5f8HYUD1PJ8Wzxmf6xvaCsM0d4H6sfBvZ.zHWn9_AItuDef8YsAQ_AREXoXiCrIm7TpLpvUN4NMgMQGC_ROzGH_2cG_y4rvuiMsGp2C4hSH8myz6iebwxIOGoJoUbZHVzbmcHdqQwXW5biS8WQsYuboDpSjfSDGUVtwcOO6uEK8BW8OwxYCUFM.YcEF_zIqQjMG4vM1lxZRj9IkNhjbUf52HAVbZoQzZVMhwD9jph_XOkitPoyYyxJWlM8S9GnZJY7bt1MQu._P0V1L1wamp4v4kvBGH.9l_VdkuztQb45EAjW5ybYauoCBfBGssDBwj0nzrQk7PRuk69t63GqrBLDSdV0sWGg.n_r7gAKuusPnoE8uNeBpJ3EjLlXyC_L9JAhOrpTN6uvy1awmGY._4iUO.XBpReyR4yJEJ3VWH4ahtTVR_ytqKHRqv27Nit_Duy3VWYw7Cg.nOiuf.sfvPnGJYKYLH4hHXubZm9XGslF3jpMXYrT6QyIEgnaq.qcQj95wIAVw6UB6yL2Hc6fGc_kKGs5BQBx4t005lBDvi0Ou4sjWbC_GqUStpt_KM0WkV8nZ0XBI6H0cg_ETFA5V6RmB6vqUBFh207Ok7027q0eHuGez6DzZ73tELuPYUwAp5JibcLanmbAksdY12BP5xVL2qXncX5NWOoJb1BpTMcYJUKZEBXp7iIzuB59YlY5O7RMqgy7qJsDkfWv2PsFq1Ue9FdMAkEzVaWmHQWdRrs.zYux6DCDYSFpBTafr9PXraQzwMnRkhKbu8xjjKw7ecOYebQzz4gBKJVoWCzZXgrcDTNnENfgM5dN7_Xs.egKCW5vfCxpqgQaZvvaDPirZyV1rIelC8LMV6fOHtTdLdSmfKj0Qig4CqMeeykH8fQCvuUBZQbEuaWgGpy78PiAENg_bJ7rk1YOc5SFges7GhuazVn0lbdBcA5L25Gx62UYCxM4xkl0NrN3pYgmQD8EDwb8OO8pTkxvzpQ3ZKYFq8PyiFe6hM0zomR7fxrP6ihoZhWZS2TUiE.HubxivWMJGccKbJ9Yp19z_bTKDuQ.REFGL.VPIIYah4Ome4mBLOCrA1nX6y.IMMwpIcu8uhRF1uoF7TW8VQkb62B76eAKtHyDRylsWHoLTZgT.LIdyjFX2ckdG9pFpKqeM4i_4VBmHWECqkm51ToMwztPw4yg9Txk.PleiNfpjk2B7TywUGLni5vK1UOPQXzUC6jNG_JV30ogy4skV5E0cBgm5ODJ4b0XeFo5KPTeEkPEI3lANJ_edLpw1HFJtkKQne8oZhVhFbZNVhJcmcgSwD8Q7r1Zu6UgcpKdkyJZbA5VTnYRiiPoZMBkXvhSMTZBpIjluMLHeE8wGotfe1qsQ0JPZfM3kKNXeytv5DtDfFGbD9crkK0WMli54VPUNSSgTP65aJMT8VwM3TXOnCzOFcnxWOFYqlD7LAzVCJklzRwBwzksQQ5xnvVAacvKmuZfFkJp_Exvhnn2cixspZg9ekZM8GH0eBy3nlqQ1vIHyJZsDu9REoW1dN45shY_HlbkQW3tg9.byREt5YBBh0whiTl0jYS88jhNsGs5Wg4GPoQAk2QT9mZkDuaKYpRc1nr3d.C7v9ACzmBBzhkaIAiElFPjzYCMyjmQFVGNmGL3HQHhp4Mcf3eTZXmd2XivPXhreQ1_HKCIv1IArYNIIavSxPQh4"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92dadb927a1640b4';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, "\/1063.68099?__cf_chl_rt_tk=DbULajd4DIjBzQ3nobFIBjPEZ2m8cXXdKzUxC6gJvok-1744210655-1.0.1.1-nP4IzZxr2FiFo06zEGYRfwGaDA3EHj0p2GIK.6OQl4U" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>