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: '92d31b21ff33aecd',cH: 'vugs2TG4rQx6f9XLSC0cBwgtXBt8CSmjbMCRdcpFnK0-1744129372-1.2.1.1-n85e29JSCLwkrj2z3xoKSOOD.EjPBfc7Fc04RqYCgQM7Tnmwc_kenx.hMEcFrh2g',cUPMDTk: "\/?q=rf%3A7201443&__cf_chl_tk=wMuiEwJ9T1TrRNm75a4L3ywhaBJnPQ34DyDRys1UavM-1744129372-1.0.1.1-.SRcmWI24QeAgcXfhRWFSEEqxyHcwCMl.24Y4rdIL2Y",cFPWv: 'g',cITimeS: '1744129372',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/?q=rf%3A7201443&__cf_chl_f_tk=wMuiEwJ9T1TrRNm75a4L3ywhaBJnPQ34DyDRys1UavM-1744129372-1.0.1.1-.SRcmWI24QeAgcXfhRWFSEEqxyHcwCMl.24Y4rdIL2Y",md: "pfl22U7COOlsjuZ3TYsDpz.6DBJEP_.BciVrthWzuP8-1744129372-1.2.1.1-H__6mcfj.ZLkbYD2WGJ4.t7xwt6Ty5eONYJiMIzkyD5XeHyciQ85Qxbjy1syq.QlAI_rCloGSlJw8jEhJL7e.CddnuohuTF5LRwcJE5ev55kym.agP6LrWbf_mCu9KmUgzSijuaUCwLbX1UvU99LIp.SC.1z6825O4joQPtjl.w6UB9lCk12mDAlS4Ap9PFP.5Ir3ytic80sHuiZdyxwQhkoDYJjFywWdlQ_GerzMfqJh0u7ssTeyxMUxI3JUbilrj0Qj84rreAIvs4F0QJ3i2EZ7Zx8VEthiMeDWrw3pQREK8PtnVyNatYRMDEnyWbQL0fMhN9YpKsf9eNRK7ixPW2X6pqPCwflnh3HaaNz9uWYknLTtjfg5UfJKn4n83FpNQ3rqm30ZqthsGWRRwzUAVHLl_H7XqQFrT9WtSEKsj4igWRT2IxVJsngT2yG6i6.70RD_dtzp3spZYDASB3YDqwRjy3DMfOeE2bUK0tVqxnjBHBEqEDr2PSn0bqVavOWDfH_va6tmudwVnz0dIOSGUt.NOvSKRKT4MTQfa6pp5HseeJqARCZHnG2at4dXHvufH7GV7uGmEa.VnAYAzIpY4wfZ1gyyyUbfGLaoLJzerbYQB0auK829fw9lf1xm_eyY.EG1q59TM.2EXAVQhhe7bq2GtGACJsv47LUKiW4pDdzfQByxTJJSzCDFYKFqrsleifL8tIWAV5wElj3DeVlqXtVAPskrMQWh67N1Ky1d4SWNmc21_6YDOXU7H151xR_tcMqtOJLcRPA_byNelShaeYKrilznuJSwEBnIC2Jvj4gevNv_7aepiGUp3LaX5abBahzlvl7F8uaaFoiRN2M1xW.TzHhYGdsLvfj2ugwm8Y0M9OBwadZAi3Q98FDNwWST.FbXepp2ajP9IgrMgEvkpx55kw1pKLK8zOtJebZI6yB85cFsa9lJcHO4XUpEENpKcuzk28UsDBn8ZCnPg7rpjnYUBO2hB3GvujFFRM9ebTLlaILJ51TMPEe8oWCfxUoFVkO81FlHFzn4vxKiyvFzxGQayKEFY1Unr3NHhuAjE9GgtfFcl5dgPZP2V.Sn9JE7_wXofTwHIGSkp21eXoX3DcbxvN8m9GR_o5JMvwDQPlHVQ.v4fu_d8cI4GAOlCfmCOHiTNMCijkG2q2atu6PH9skihaf0sei0GOUy_d1q.WZ9vNZGwA1Iwh9q4XlWbDU",mdrd: "pXXygvHESS2fbibiUQ4XWAU2nn4tb8smaKn2EMx3r4E-1744129372-1.2.1.1-.sTyG3oO3CJaW5C.TM7Ec6Ukp2ueUzX4kfOTEhXFoDTFEGsJU1hu2HR6QPcnizi3VdPq9b000gV41o7YFcO9dD7FrZ8zBk0jNp752crhTFGS0cWK6.YMo9zCM18kGmJHmdnw04K5iaoHQAux_r0VnKgGeTs5KNwtfd02a5C86kDMBw7_.8tFp4G8cGk4H7uvBR6VQtFDdcN_ZdPlylFRhC6N1P3m02Ml6nn_qpvbjTOF4pIR8vuEYqDMBG3arLW0nVOuf3.ttdBlf3.3yCQwtXu7t.ExVXedD9pEvlYRwI4e_yPyw93nsl.3y1IEs.2.67x3_bk9Q.E35hkOPSSsS8yjFg7iGzSCuUAACh5PxK5rDEUUimI6AOgmc3W9n6BZxecyYskpYskzTMwmx63veBCsRypyfZWFG42FZsp4IAwnr7W4khbkL9zw3VMAIHkNqZTVk3VdUSQ3EcPrtOPljn8VBYSjr141AxFj.Lvl_iQQvdPmwt7oj0K9dviCnunTUAyHSZ9krBPieAFmF4HEGd5CRwqXrxgAJAuV_qU2Uod7QSelKfu8tK1tdLxw.UERQDxydJPeI7AHdU2H1O5TbJIK4OS67MV0xMGAkhifYgFLlx3x7NxQZn49b6GX8qW1tq44goSjZWAyBm3FhYf2VJB61M4j5THdRF0lcbJjpwcEOxrhgxY4RRtGwSNgm9EU3UJVi38uID7zzZxXAhLSwi0B3dS2b7VYbBjEq3R0FxhNLalhmOGRdClxsuT0kRliAYCwG5hNj3cMrP9o.cZJgggUaSLi1XgdQSBlNonXbFM8djm7rlcXDBkgQrpCFgusMFDlEp7hba3HFLwIrmmMwSZqsOQdfTL6RzC8aIjuM2iEyaMaAdxseuxEEwYpUJ5UpIBxUL8SEVgCNLTOfgFBR7zpM_jtDZZRLnhtVLoeFqaBa3z9TmuqbTeNv5IGzFO06JuhM.z.QqKb39tErt3DPSHxqEvZEXtpOWAzhrmrMjokb7wY.dgyrLGvRFY0HBEOwxBK2rqyPudTaP0k949mc_km454w4JzP_GVRggp16nf07hlUfVrPKNxvwc851OzHvHnNndjs7mSYxF9P86Mf28fSYr1Uh0Hegq1vFAjiLYh7yIUxtqA05EYxr5Wzz0p6R71AXNx0h1sYDrQiecAp489kMRmgccDMxJD8tam6v86uHqG4MZIaQIxh8ZTakuHXlNKsCqBlUvtujysa4sTdsgkPXXGK74.fAaLAdz86pCKw7AuNg1vOeZiCrm1AhJLMXOc_SaMosfYLq9ctJzYSdfmPu_v77.c4HgEkc2qQQqtZ.AF8XqEdB1V83IHENzv3tgFEm8sGDg7AmauFVGYlSJLOv6TfjBUlQ.Mjbn3SDgriLrfPmysbUpfWBHBdrdl.MQ1yZ6ls.KmaX9qxgQz_561_cwz2hHLGVuMmQM7XH4K6kJMkOAyAC_c_oUIkc3306tceCc2imVfqwJgZc5xVWmvDUnkt1LS_T.wkjVwl7PgExXI12aGQZPbdAKZ6O3vSVkfyjKrfL0QK7Ilite2jkMzjmtOgUAcCo7OU9lwSuSRmbjrG9_a3DOEy3Y75Iyp9RKQpj8cVikW9tOlrlIGE5j5Ox4.ENjs4OD6HvdzZAfn0VD1RGUT8Yoe0Kx5Qy9OrDme6c9NIJ1Tkp9nC7IHOi2rpTSO9zEEcBZgwMkH5mowsZDfTEQF4Kgv.1Y0rb5omiBTftVPvQaEtFQBcxxhmW0PSJoImF2AkYwSRIjXI09VuR6P0jI7OhVf9dmDVgzAbNzLaKwP1poqDomnTRQRg7yQ54RvZcv5irKcOC4UQepX7nYBH.qGuPl6RcBxDvidCY0bvQ7FN.70awLN9fQq9cVs8nEiLB2esAZZG7hZuBlv1NWk32hHGXrGuaNHUJ2eL3dog9Uqvh0KrULkGAp_5V7oZUHpp_CJb0vvSght_B4B_D9IunL9MWGXaDBCF4F3mrWlRFS86j._AgdrZqiMjBBBlnFUu7GlT5F88VP2oikseQqgVkVU9eyU0rYsZK_DV"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d31b21ff33aecd';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, "\/?q=rf%3A7201443&__cf_chl_rt_tk=wMuiEwJ9T1TrRNm75a4L3ywhaBJnPQ34DyDRys1UavM-1744129372-1.0.1.1-.SRcmWI24QeAgcXfhRWFSEEqxyHcwCMl.24Y4rdIL2Y" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>