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: '92d7532d6c7cfe8a',cH: '6UjjPr41iJR3a.nA.ioJ5ODact4vhd4ukFoy72c6bGQ-1744173611-1.2.1.1-ytMJYtLY9vlmqr2Ra5rOB1DS4VYoZ1fNg_3gNDPkGDRRVPIISYWdHmJXyJk3epz_',cUPMDTk: "\/1416.92162?__cf_chl_tk=N97stv_1FFzDAKXdoA00GlD73i.FV8171l5NdMoBca8-1744173611-1.0.1.1-1mkkPaMAjWImoSbbXVlQ3qYhaMNGecIEcRlqdY2y.JM",cFPWv: 'g',cITimeS: '1744173611',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1416.92162?__cf_chl_f_tk=N97stv_1FFzDAKXdoA00GlD73i.FV8171l5NdMoBca8-1744173611-1.0.1.1-1mkkPaMAjWImoSbbXVlQ3qYhaMNGecIEcRlqdY2y.JM",md: "EYxxdV2.9KKTJjw5FrXIPj.NoU0dfNk4Zt6xxy.ECIg-1744173611-1.2.1.1-_awpIT53X68bobpgv8kH_iD_q0ARtlF0iiw2DVhk_Gv5xEKmVTzmz29ZgduKzLh0VMa87EUbx.olK76loOkg5AbvnWApYakdSJ2_CP1ASQrkpGDPxAWXpLAVYUD6NO1MQ6qkpLMj6o4aN44mu8ksZ6roT.V5RCJlnQ3xQQgXfFoE2s.m43eWwQUikUUZdNuiaRTT2z0n31AzqvhKLdDmp_lezE4OS3GkrV6Rj7YnLpOoKxKeNbHhdh6meoKHUNaErfAFpskoUkgiVWCYGaRVGsUX7Xze8Ez_LpWngbaAok8DyJFrw6A9I9TNZThCzWiLUFap9IG236PfeyN8D3ZTvW_4mQ2qztxkn6Pr8Mwe6SX.IaVfKJCFyMefA3x8gM_Jqxdk3XUtI9v9mQqz0hTzP6Wnh9pAXl.FZqQNOOahgHXp760eWZiYtcq4eUFxPOqFZvFF6i8k_5QOW50CIVoFmKYyEIdpoN5WF2qscOJIfOlkYssNAli4ZrQ51weVna2BcHdSvG16xjQiSz7Zbe2pDkxmse.24DlktWMN0hQ2uly6qFL8bVha17SEyKtoQ6EALQFVWNkINdSjAD.QLMCfFpCz.75YQ0GqoipggYqGqDLO1_jEe3cipwX6GnQNvN7lP7Gj42_mMhHjXWK4abYm.pYPJJefd_olqOPslS5DTfL3Pk048If4S4odHoloS2Y08hYRbCMkjfE750yFG1dtGzimeUFF3X9EheepV43v_aJZPeUFGOj5J6pPegEOnX0bU2x6VZlIpR3oIhb2nJViICGTwFdwGYeb.icHlFylr7lQyGjqf4VzCnloLS2.f1LVzMd.KfeQ1lV5pl_BAQkX4mDQ_44MeyCOfTdGHljqj25zMbfPfbNkln1KndZDv1Qy0eDKlrHF3NUgrftkW4pgApiSCXQYoFQUjOxK9Q_5xc2KPYN3t5Wob9rfUKKvlnkzP.rjVP_97PVeQn_PSlo74jXdwjaWqhxsOZPNNI0jEAnItpAVOBQ2M1_kp8uuz7UdbqEUvdO53gSg.PNbPs3oYw3KYucFby0OAO0iP.OVyS8.J2TkDRaW7.uJJHEMQamqOcl7xg_l8PIxJ_DBwiibg_RRLqdxokkoMhGg6nWeUYBOLL1tnc.dWtd.MmzRdnyn2HEFEBMwEltQZZpyyEXY1gzXJiZy01Wd_5eqv.I9t8R6DSI0W_QN5WZ_ZVEG17HG",mdrd: "b606lxczVu3ATqVr3FDHGIyu0p4zPe_INBmrI05rCVc-1744173611-1.2.1.1-R_Gyfgs6Qg6GUT5o74HGJX0LnzmdBOxvvPBa81aOo3TvS_c3fWklZO.gO7E0gjKgVccWbir8PtL.3l_VAez5VKznAlGVegOosLR_tI3RJ4.EO0oVjTDbxAmdRUNejT5bxjg764cp4LDaLGoxuSZO2qtKP0TKw_VNnUL6YUAlCp7rPb7FnmPAyE6N.4B.FIXu0GkxlA6SWQd6VCh.9WGpl9BOfJuk5CMfmC1EjwQQpJMs04ilLHNp84sCGRiz2JRdfhIJBQSB3cSaZna0qiMz6Tf0gdix9Zno4IJp6aSYW5XcSjUypOVsRQ4kngVC0x8iH7oofDnzMqx.6KUFkn.PJDNKGfhtZlHAJJtJ9MXn9dCHl3d1QtshjRWTgoXLpdpvRgoCtdGAde3cw5s3Kr54JRv9kbR0grHxmKMeCXG6q7ZAONC6eYOiQZuU7rN6DlsZB5C7RRGHYVgfAkyve_Kmt7jQdq0LtDXJ_KWzmd_Xx91Ji14hHK.A0mVmUqVk5MSmqrd2h0Dx2cRuHfJcv1pxbnYj_bLUYGYJ.GHi1OgaXZzsj1hX44YNDR8x2ICh4HRGvyqKOgEVahHO3OLwG_wIu05mOgaF.NASfQ_T9Z.2qDufuXHMsMAWhsPR7l_LkIkJaaBlS2FouZTYaRZ83uPpmHW17.lHWFZ.5Exqt6sfEsQeJNhT3YPHX44yYbZ0c2WIFPqgr09LzRpxJLXO4vHTvb0VAqtpCSgey.GoGy_seAV2hsylQk_xmsUWJl2HiSkMgVoADp.ygid0tCZ26MyRaV36xvQNb96Dbcvev3XT.4MtI94YwVBWWOhYJuTp402VtgGc_aoqKRXRHD9zEG1H9m8R5hPWrnfQ2NVm.OrgebTksmJvk3I_SDdTo8b3Q1n33mthFiCkDLSUY6qiKhb72uWw1B0lPPQF9y79uVoUvL8qciiFWhX8uu4eKAs6w6Fla5PbB_FVmqGCVf1gs9A2wbmvMFepEyGxZIzRPk1JLlsou_8XNJ2sGabY9wRrL9hurP9JFxSUMi9aEB72ryizqe0IR3TF9I_a.qo.PFvzgc9drBeAfBvYBs5Oqt44UgoE6.uNZcGozo30Bj0.4pR_p79m1Is53jfTu313u0hhLbHvjz8WzHtBUyZoDzdRMBbQu01kkNg16eELRfOyCfk2ob5nM483WmuaPjN6iU.YClXRUUxpp4Ta4KQI9xpDNYIPtHy3H03zbXdds62F26Gtd20fJ_5D2weG_54rQbc3zM8cDo00e7Y_ZqoxdNW4nKPx5MpzX9JQMEaEYVnIjQpk_fsLBtZKnM354DS9eAsQ3crL_yD57DnRTQPxACzJ5IRO.XvXwFKOhpXD9NuOBcYsqUB6xDy32c.IGY_aLOItwNMlMkg8Ojh05eD6TWrPu5fuakHSj4M9rHCw1ZrK1cn_Yzo11.UzwNRmcRfECRhgDXCWrXMDFlL9sFzI.tpe8oRw0dRrsGTS0Vj35dpC8b8tMiHnhuHi6bvr5lokFk4x6qjE9NgFvcCBMljzLmuKY_w_k9rgdeZfi3tAW3uZKm0l6ogNYWjswGLHcNYJozI21lEWAc5H7XmJNlBWL_4ziSKT0_8i0r_s4aLWb8ZEP5_WSog_YZsdGZycgC4IiH0bZsPxVVC2Jf3gU1gxQA7ujMyajcgm25ZwDUUQtaKAwK1QOzpuoQP8ymRLnVGRHHCF81yiuoFDW_2PFkDMgDbr6LpefOl4Vflt4WA8vntS9byXC_vJhi3PWvatMLc7KK1hXmur91CzTRqPw7kfSj4fkUX3z2LfDOt0YQR.gmC_VkW_6bIRFOW7rkZyatpFtku0kFgGNZ0ies9pVAStEVB9UTjWCL7engkJ.U1kq0BBkioRt0ZN3AdSkTpEJ_JgWWcJSjokoPn1JVnLg8jdXi7DhgSQVUndmj_jRCHK.Av6itcVgKsV3xdLu4UF8mqc2W4AneK8Bw3F8PTBW5zsbV18iQsLD2.OMRXFAC.5HZ42U6oV70lWV_UqroSg_pr8_NZ5z3K7Tgy33o7wTYEakQ1MGlUb"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d7532d6c7cfe8a';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, "\/1416.92162?__cf_chl_rt_tk=N97stv_1FFzDAKXdoA00GlD73i.FV8171l5NdMoBca8-1744173611-1.0.1.1-1mkkPaMAjWImoSbbXVlQ3qYhaMNGecIEcRlqdY2y.JM" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>