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: '92ea0a7be9fefd64',cH: 'Lcfhs_DIGhB_PtFwTIBO5x_1LfwXV3xvfrYG4xZerqo-1744369863-1.2.1.1-botUdORrYtDtD.6_gauHmN1XUqeco7eIjuXusRjSsFmzChaqA7edTco3dFQU5rvr',cUPMDTk: "\/0831.68098?__cf_chl_tk=rD58rwBraBE_GxUmnBtRE5eh1T81cSreUlZ0z4QgEwo-1744369863-1.0.1.1-ckTqaiqLfUtjzbVf0asYyno2HKO11Z3oUtdm7Fv3iBU",cFPWv: 'b',cITimeS: '1744369863',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/0831.68098?__cf_chl_f_tk=rD58rwBraBE_GxUmnBtRE5eh1T81cSreUlZ0z4QgEwo-1744369863-1.0.1.1-ckTqaiqLfUtjzbVf0asYyno2HKO11Z3oUtdm7Fv3iBU",md: "PXhfwYTZrjufx9L2MxkZHaNZfVFO_g_zps48Yhey4gE-1744369863-1.2.1.1-ZazD7pwc4Ahca4O53ZfaaztZat3YTNCydqVCp075xCoIiYDW85h0DWR3NfLtxOFWHAXtP4P_fTbr9aQ.NOAbry9OEhOESbQi803cJQIBS936cV3MnK7PNvC.qvJmu5BcEWehsW7QeIcmFJ4b46vpPWvvZ1ZA.QTGLgk44OVOnJT.I9MBG3OoxlFNPPYXpk9NmuqGOFSlfG334lLE3AKMWgK816UL.n_cAo9aDrcsU9gWn3jCAxjiefbUTLfPJ2p7C6pBeQNWl2kQ2_BjYWVoGBMLQFtctOkvIrhjLTktU8ZDMrtiBY3GzTC6MAwve388UBt.uQGQb85V0K_pmt2u4SvAP5wZya_0Yc4uoWEjesFbSgMCeyVlAB2p3x.jFF2O7i0qM_8O9l4uILlHO8DoEgXK177P5m2XjtWyvMa7MZVmhUcHGdmRwpxXDPwjvPO_ENPkIAcLM38GjXi7AaqDnX6YqlF_QB1VahEnjApPfCICl9r_oa5fqmY5MP4q_OpuAu8KEbeS6PaeseglaZuyiUt4AoZ9CklYwQ.8VZiKG8sls7Z7Nsqo2FvY_nK2_VbzK_6fZ5J_iRP5UbkwdjGxw1BQl772Hfhg0CTkbmJ9R88TtlBaZzYZfVnz8gjGR_aw0ChHzx.vCaotEwqw3JWOtx9hHtVfFcKseOhQ2S3WKP3v1LyxapMK_moUnM2pU_mIJSEJWeyDNERQoq.38e3gwUo2GGXr59mIyRAIkolTtFLNOdQXVYSruc68QjqunoqReJHDAFfKgqJFeCS8pO8_CY.s4ajrgZJuxtNLM8.vrdXI3fwlXa9DhhXN2zWps7.nOt1el8VTdbMoc6weehMxci2VCNbZEyDx7YmPxsOPxM.zvbmZ3SCVvPC9JNOVTwT1.M_2h6pjyFo0vxR2nOKWa7Xnznr.MbpIWRzsyCvb2xndqT0YzJh8HPBCUtHM0H0JSzVvzS9RJ8pdtUlKVa4TyxI53P3vXiqmn58osaikiJAIU6_ti0pckudcDRbMYGt8uo9ByEb0TWQWJwGsk.X8VEaIuwfYizWj6C1dQE85NiCXxFWBO_QHdR.Sl0GMfYzs3oFspKYoYUa_g76lVWCjcrCQ_eSHdE_HaFWrmyFdqgxaITtU11RZTEZMjsYVxp7XNDJNB5i.x4FYulx3SViAaitTcrIJzcQxeyhVkmcovlCoxRixF1jv2zyXZxbqQIsO",mdrd: "frQSmainOuFqk7Vx4prtqalKVmZHOjejkv4SiXZ0iNY-1744369863-1.2.1.1-GsQ3dqAe534humg6nIUTu6Cb4FnTsv8zM.rBuVC3mnP64AyPH_q3TCVq8czVLXHVDnywJLppH.B.oDhkTkYKFyc1XPct6KjdlPoTA9KHp6VTN3BNbe4HIVs0XqKKVKJLFPWsmOiDokUW20mGRLCoewnRnEV0F4CT2D_PQLajv9a8GMspzyhjS9AnPbuK0tDkq5oF.Kdfa2VL4EcWIH4dDihI.ds.u_6D7B_uc5cLdPbcp4jHARC_ODOXR5ozHZSzjM53DTQKxv9yPwTfKzoXkal67mCDV38JdSS8i.F7W4QCBrz.3eKZ2AA3fYJ6GM3N2xQ2nDCrhu0hKluvwA9hQmmDVtUOYsjfI379A7q_fTB6KHAxY8cbgYFHiGvctZzR2TOhdY2oMBs5.M6VzXD8IFKFS_JWzBmWVt06xNFawoPANjeqW.T3dvqOru0KQp8juHIzKr54Qnh9bhSELwWFA.DupZ9bmA.71OoGwq9.MrWoOJ73U99rEDvTgLz0kZh7jCRV6toQsKSERM7Z_LAA4Yy1An_9IJ503K_b4Oksquj397.emAftrCbhUfD0lVS5teu8OePm1vcd8zJRurENyoUw6l73TVNi6Tlk1LxBl6P5qC0Ebf7SdAhc8nvT7ChC6vnz7S_Am8bu0sb7bDLOY1n89rnT2OYiVQrZUJrHFNml6tD0s9e2Im871WYtx9zsCdrRt5tGqv8eHZIrOK0vQrlkvtpjwn1YdF8KF.7m0kke..unlTF2YHVFM_DvspIWxyO78TAX3jThtsTS5Df9kv4K8jEsgJAFpD_URvHDLqsGqC.j_xDIjMo3FdGDDkfGchtXJ6dnkBldAB0U8ZAKqTUADUNcRLbZLIq_jYAvwZ51L8kkGOOZqVhKRuVn4ndTEPKBkOqW61Cdk1O30skndZxW33we1Rxfy4txTPoA7b_7hWM9KohWp2hvCZ7rmkZfeCnwV3emloyE3eC0WXY0iOoexi2Rrc.KvdhRKeq.aiAzsyTzQ2fKJSo63FZVT2CEQECbRiSTv8XW5z.o.yTxIDMAFe36d2gOk79wIM3p6mXH2RMe_4lNt8USYUN9YoIo4d6eaRvfRMh6MqrnxsrUnQ_CjXecO4k4.Hqyqh0jEmD_pNBx54GpkWLiX8c_0xQzv1SusvHcqUzrQ0cU4vnNXu1JGZ.mkXrCxtnW4avZpwnlYqrCX5uTjh6lUHTJsx.jsjPqHopAgXJOixrNV7Z.dEC4GC.GssSr0YFCdewA6HfiAMZTDDt4TuWkQvy2ux3deVmdsA2_zL.lyxZuiEHwrRNQNELSromXlU.A4l0Os66ipKLhdQivHvmWu7bXy2hRd_5gnBXaxOfzphnOE9Ju_GOPsDAX_GPsnaIztWyRSngFcnM54KDI14zsg11ZsQqEx8SBqJ5stJy2LyiVXjQ2A6J5PYqojqvSEeQL6gfxMGHeqq56maUSwS__mQ0l1MJqXCNpu0a3zfIcBbkHTA2ozWWfUV.skwO8Tbo._vRczRyO92zEZLliLjk8P8CrQjPWutGgr5mnvt2Qv6q5M.8kTC35b4Fb2L_n8s2ZuBCDCm1_4dMayOxCViwQfInSkIexWLb4CN.kX9ZeClmgdUlDdefNDRJDDGaL2KwsLisW5chINLtSiQiNVT5KKgpyYOYec0IcLQAhs__oRVwxRuEEQZ8qoo4tMP.6CqGGdHCrYpCiNHEZF_h2TiOkqoCYJixySQxCL_KEsSVuRT7ATnHhH3H6WUKaqgb01iicH1w8vdE0klb7o3iylj_fV79srUoatpEjt0x44Lw.ZPBv7stAxwTQ6QBCZmaXTHJ0TPRGG0fgmKAuy8HjFKvcHuO3gvCL2z3nwVw5c.JbFkUxJKxqebidmDN4baJRocvwzUzimcuLnxHl8XNcgfk8lTztTJjM5OS718GzrTi2oElPxzjACq_qvPfmGV3GJmLI._ByYijDmjEYfQOvPonNGInqME1kCWUMuuzcks0BbCM.t4Prld5GDOOS.iZYAluisLvOoRIa6wxCASpGiq_UKCnf3Q._"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92ea0a7be9fefd64';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, "\/0831.68098?__cf_chl_rt_tk=rD58rwBraBE_GxUmnBtRE5eh1T81cSreUlZ0z4QgEwo-1744369863-1.0.1.1-ckTqaiqLfUtjzbVf0asYyno2HKO11Z3oUtdm7Fv3iBU" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>