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: '92ebfaf17ff9f8ff',cH: 'Zt76toJIuVC7EtSqacWqxXoHiih7wn5XHQzyIvsb.2A-1744390198-1.2.1.1-cmmDamMpGY8JQs82JdakEXo4y0d5YEa_Rtd_97t5tgTH0cSgBSRH0LNcadBoetwM',cUPMDTk: "\/0243.44006?__cf_chl_tk=MXdkyJcYjCbJ64Va_WjhpO3aVl8owpxeTnfAOD2wviY-1744390198-1.0.1.1-y5JyjbtjVqvFbKFCkms6ABO8373mT6OV5oZe5JoUiks",cFPWv: 'b',cITimeS: '1744390198',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/0243.44006?__cf_chl_f_tk=MXdkyJcYjCbJ64Va_WjhpO3aVl8owpxeTnfAOD2wviY-1744390198-1.0.1.1-y5JyjbtjVqvFbKFCkms6ABO8373mT6OV5oZe5JoUiks",md: "aF_1NqIDNAYAFldU8qyVVvO9to.U78iqhRks4TyOki0-1744390198-1.2.1.1-dRwRxm6DSxfXFHHRgdD76JfNFTZ920XV63Sr9qP5AHRH2K9rY4G1YD8vkjXhiDxxFBzQcMUlVEg_TdTdplK49RxCc.C1pKDBal9iRJK11hrMqe6dfapaDbfZDdJmS5hYhkjFZyadMKII0vMtUzc237OCyFbjeayOXJtTYaJ9WH49zRObC7vKyjt10dTYPddFrOPee.LH2i8EIDor4cxgCD_wGiMI5OU8YHFt1E17JLHxZey85QRhi8iv7Dro9OfocazoWTXXC2QpjK3.slXg74nB_pC7dGz1Y76k7AkvCkj2IFyD92G5qf_agNEt0lYXIzJKbItoIHdvKpPLvCdSIOzeeNci85i3XUoAb2bim6QyrwYJsqSYjaFUebriYR0WRjlTESgapBH3z3iEvFicxX9Kl2.326sghvJ1HMIDVKM2elLV6YwPoUvknQ5vIutk16YamIfbaO1aoItr_Ps95bVh_JrgtdaFh3xlovrqSqQ.6111VDbUm6o3MwHsHFaNzXwFcsA9tsVOkQ60R4SRqfqmqZPJk4mSGawkdm724irwSP9C0QVt07Ntb13qoIrXSsTFGuuMCyFjXr6q_t0Sye3WretJU87HLtq2fiqtRV_tQ9GlZ1ItlFUDL.imoFqtzU7hf9YyCU8P4.buLBK4QHo9KfA7OIPzrfMTFicuIMvPmbGt7MU08ONrelY58LIxpg9HKjQPUvyZX71gS5F7IS22SnabtvoMZKMzjH4aDILxRkNfSeBb32jw9A9c9v2bQsUDNqAR7iL1m7NoPLJEYuFIXd7a0.jMoKLN2VEg2SDoVWO9vzgVr9jafYPkRu5wfeb.9o6r_Oix3kigeScMu3Ux45xk53HQKTomoT6cUThxbN.rJ.gA0UmHK47hUijPWxsQ4mjqlHtgClRoHBNgMFMm5nIh5cNIWkavKy0sRk44NjTrThLMQYE6y_wAPvgDT3l3cFlu4e5NM9F1QL56SKkQ8D_Y8grO8gArrl1ca5C9KF47lbsB_7.lf.37XWxK5jnzDkFfCwoNNf76Trp_tw2VYrDGnVb_prlhS3XOB8hIgfaZQo2QqJplsUryMaTiCExS9fJFNQ5pihxYlOn2Eaznoi6YjWuOZ8H1uIh1JeGbJoY5GSMg8zX6KXaa1QtMFsjkkYavYiP1B3tOcyI09_dmQetkazZLbt.Dw8qVNSbrXeaCQArhYqANGhOwyf5_",mdrd: "wX_LBrck7ntcZt.iYLMJziTSNURPAbgQcADrwA0NzsE-1744390198-1.2.1.1-.qlzGbSHwxxoS59gnaQlsPOtrjQCP._qHlI06EM8DjYcBl1d8scc955StsTqvTIaWVT_dqvK95FAWk_raqbYNTx103XmdqFRGKbwDqltd1Fh4U8hawx0XvxxEe59YXhoWdFijIonTkw3S5FVBL2JFkJs5Mj2Vigz0JFun0tmMnC9yQBpfBSjqht.vKdsyupRkbAfOv_mYhaSIQ2aIQZHU4fANNpcLOErESkakcu4ps7f833RWtsZRQTt3Y49m56EY6oUcJ8tJcHb0jyQiMdy5hGLhfjrJqveLWZNG4IT29XtpdxCAsvWBmLfath3_c8_FUaRiX__BHCxLqtE41tI4QtDEkScNOv2hTrLwcccuyM5JKJJE_.faY_k0j1lYfGX9ZqAyAAKgqXA_2US3SHMxbnAO.Z1i3tQkbRtpjVjzfsv1YUAQhmPtu9y3tI0tq5Xl_gojM9JNTMOdgrcLZ6cvL.aNoRkr6bzw3Iq4lmKAZYvlfiJBoh9rOnB6ITj_zs5ikk4_EVug8Ixn63GNBZ7RqNrobOGwVOq8bgFpzU_Ewk029oomIFH7y89d68TQXQ0g4KR9Zq7kraqCMo3UBU0a8cJwPvZ7XMjyWPZrr.W3oCIxdGABodgeSRnfrp4tIt_d6yrkfTncVEhhrRSvbi36oK3i9UqbTR85BLhiy2zDMKHlE5DGHyFHboqf8FBbDdFY_Mwzv.HcTC.wovnvA2ux3jllGEWu_.gpWZe8uUh7zvDcfGuaf6wKQMDiUB2zI7G1yJIzC74AHs6QWFAz1gRc2eL26ySFAnXHDnlnHTgRN2OE.3LmOioleBNLkp7x.5a7J87SZXk.OKaB4sapZ1Zqy6NYZNz_n.UacW_lcnwP18gDV_AAZiZnw3sLoFuppAXGns9zYYuD9zX57hdRlkYyHTEeSCp7jgLZY2JiJltTZ.FN0wW5g8prDhBx1ozPvtFFOLsjZWSt.5mqytxUfqHm.aSy_OOUjLcsySU3TbcaRMISww1ZoCFHK7eE2kdbMjr7ruq.Qev80GZ5bbsnCsCq_diquO16BmJjuk.6EUZCbbhbRgrnY2KOXU6xCvKQiDXIOsFrX87pGZoYUcoOS96se6TXxlK8V_GOS7qHNW2ZMPyaV8ePzGPGzgnknT48Y7ln8ZCwW2WOFuXjAkrNcFF2Z.1cHaUAJL9cS2JJA0r3VOL8bOfAoQn4pjyw072Ipsnt1fzuFylfpu7DfYzHJA0tVfBWRDfBwA6yIeNgQBENDMhi1WHU3jv1SwYqB3B7yIypYSM4AxSVv2iQdflHFff8ZN2XrBBudJZIEZP.Di.k.ngeC7QJ0vq3R8SpJQg47nT023EPsfQLcJfarLKa.WTmAVU5tV6JEVg_aQcRgnCtiY.uAywYA05mkZD7EHOSNgmI.98YrWY.ZFI1QP5uKaHOa.iIzgf6gZut69lLwistU17bZiX5zXUClpmtrG2oSs1Rmmw6L8jviBt0NCHxp27LgAwvWfVK7DD9UsCdxmlCGPbmJ__dANkitH88OcZXhUTuIua8_fdMeIFolWEFcFeTPQh.p0SibLbTguunNGZzTzE6yxuwOSlVUYZxYhPoOvzU0X.s9KP6Qw.UzOCAtC9F2DYYwEYhTTjyan9hEpW.yftwEoaBtEtVeUleKnXSYVJaF6BrhKKWhxU.yAjw6sYC.HxKa8YpTq2NhnANhN1V.VQFHKcrFU4kM2e6UeqbW6a2CxZQmLUCUxHR5gZgjkxZ90PRWumvrlPwtnDFAPdIYSG00LGwbw0trIxlC7Q8MPkRZfu8wr63YNUhm1UfJB90VJrCrTgRyEyC8SnEFoKvWmLd3WXyUEayncxVGmRiFAlP_2NhdMYfzUjfLYYfBiOkYiA2kav7GatVn4wfzg1PTnLWsz6D8nXPhLHXl4kJTNrdRnpzzbguLowNa2waRsWUcU1fgVYNU32HQ1XjystTdV38YKQ0g8X0S4NDoAnD5Enfm8_4S2JVJEbintfJqPwgbkGCM9.xa3qeFb39TBmGw8KywoRg5KFtx7vzMn6wZY3kfXMXz8WE34zlhpDap7p3g"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92ebfaf17ff9f8ff';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, "\/0243.44006?__cf_chl_rt_tk=MXdkyJcYjCbJ64Va_WjhpO3aVl8owpxeTnfAOD2wviY-1744390198-1.0.1.1-y5JyjbtjVqvFbKFCkms6ABO8373mT6OV5oZe5JoUiks" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>