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: '92e751b48c06ce3d',cH: 'DEBO_HQlEx1lMvHoyXy9O_A_FbO1XwMHxgl9stNwuNI-1744341322-1.2.1.1-b8KnIIZ79NS4Th6HTtRPtXd9_4WbZHWhWSmomGoztNmlUnFNgNySOQnGiV4Y81MY',cUPMDTk: "\/?q=in%3A145099&__cf_chl_tk=XjdkVycYWbo0CBxIi_H9VVlv8DFCJ7Uj7_4nUjjUug0-1744341322-1.0.1.1-XiQkATaGVAwGSd_.40IgoKZm8Zh7whc7i5.X6scFztk",cFPWv: 'b',cITimeS: '1744341322',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/?q=in%3A145099&__cf_chl_f_tk=XjdkVycYWbo0CBxIi_H9VVlv8DFCJ7Uj7_4nUjjUug0-1744341322-1.0.1.1-XiQkATaGVAwGSd_.40IgoKZm8Zh7whc7i5.X6scFztk",md: "_3H_XkMjJYCJKyuPFzRlJquKGrCnEv4Q4g3Yrc976AI-1744341322-1.2.1.1-2QggMvP7bpGUD3KMd6ashMIt99k.t3ExhAr3X.nlCxsd7UGvSsEsYYsUWxvgHNq5TQ_bPIUftyx5ctuHAZ2xdEZcsa2nkvpGpG9rrCw0g.2PJQw.vDM0DcnMf5_ADT7vJUrQMjrb39DIO82OwEgdtbG4VSZTJhy0D.SUTNt8_KeBQchy4J2TvwTPNflRSCzEZAG.5Y66SZthTFdyUZwbnfIdY3tLw0Lh1d2DXhYkFy9OGq6CpjZemXrqPEdlnPwAF_cXYaVbjxTMqbMjDR4P3BXk31zDJspxYdokfvV4Wg.FgN6uu40L4Ia.IXgDWWls_ymfQB3iJoO.MUGtNUUfvBdAZmxMasayVyln0aQbPDee1xnyKYOIQhh9xHf9vQQGFCO5SZuhWOET_NDLD6OLlEbkt15Y9fYO3b8yt6Yshnu_7euWxQwCvH4GXUyU.LDAP_wzzWholfuSkgux3sOh1xkmJ1G3YD0i44cV7ILxdsHO8YwsfTpVreVB4gQR7QIApc4TogYruZBlfnImJIh94mdmi8NYCL_C8ozmJE71iwVChKlmgoPUvsdbUI0cIjp1lp3dGSm9YuQIcrkotKTMfoP9fTk2fPMRdhGl9JvhcX5gc1UcFAlPzC_X7g8.TvFDGpWfQ7NiZ2Gb25O2BGCYMtxZMP_OS7oOX.7HHJmmJFrQ69cnKYoXCkSERPCq1uXZeTRMuTt2h4p_F595zDkBxsUA6QPNZFh6cQRQZr2qvrKXRjMNYy9LJHEeGKiPXHoWif_JkD0HqNIyHfOzSNAuUZlK8FaraW4VY9600yY0oYmMI.aFGUhWH5Y9ibHxKAccKNF32y0USdGDhw_DDn25HjVfCcab4sfxYCv1sFNk6UGMyB_p28FebPGIERglzSW6F3OzrT75etRzeQrFiePRWfYWMfp99bInACkEKs9DhNrlNY9HlEJtwhSqyxWZG8w8PG0FZp09ioYxOixackiV0yCH1vtdoH6u7OZAHYKOu9G7HKvS4hAwFfJAFecPoSnznwcJvNo18FYnl_EpFbS1rRR7e5opyWEVXBXUF0KRleGuHABs0PBg9LRZVjaU4j8mQW1lGwQOGzdXK87ih5253qDp6JmOSgMmnAr2Qs2dQyEXrMYLyMckaDmNttp52enbD.KrGIEQMd.TUs_7nOOlupty0iV.YLKe_37K0_7eKUG69aFK5jOrbOVg.uw5RhwD",mdrd: "MSLfPIPAM8FBco3pK5g76ksifhljbNo.xYn5ipizx.Q-1744341322-1.2.1.1-qftsubfWKQ5DLw_eNch4M9oF_ri.P28tFaMsNB585l9mZeolmsl72SwIFPQBqnl8K2FTqK.G7757bHFFoCSEWS8TM_DPNaj1MP59tVqNkUNBFGNgtPv2tE5tRrZc9zZtJp.3D7ehvNlhH6DTXxqRK2lK.6wUESC1LO9WxWR7aclXZqfXkB0iYD6WwcxsoKxWOb4P_anD3bjfeuZR2O9a.NmYb_evdbahIFTONQwF9Wf4E3qSeOvaD_J6YufKOk9APnwik2w576FibWDwl2UCU.oIUWc_Ir7y2tYyp22cuCAFNxv7oLjr3vmoL7.tu0Mncd5v4Mfm6Jb3C8ygYrZAMfaJGVhkSE0FN0hPaZbTkqYI.uUY7dGcLr9DmhpEU4mELRvgAxLwuHgUDe6K8YdrBw5Oz_vGLDxj5dgle8rtBvYbJIQw6eQCA.fbJ8Bopsrkte1NCdS5l5oRHQcEOnVMnX5WmVb7lCMPE2cDmSPMRje0l5wiZmOuVCfDf11keFgsFlG7gIxmPAYYd9kwwT7wkqakc8sYJSpZCX7evIuCNIciYPokoFMX4Qq_r0nZI3IjxBXzeh6CSGdtKUqjK8Eq4TqbLVd0h38jCigHfHRph77Vk26nVDvDrYJxZ4inqQiW5cY1bXoYz6vr2eqdB_mRmtRKCZDDZDDaEe_9bki82Z9RHZPp2wNTOplWW9JVVvjlRvnjhF.1nzZ166tKVxckdUQp82Iu7J03KczODvodnz9qsUL_ztofI45utYupmy5a3VyjDhVhqjUCsnYmeCuYKO1SnOnR_aA5Mj7DXb5wYxOzMQrUblqZj.wjugrBBI.sHBb58qUMRafOAWp9YZWzfqQUazy0Xbi7h_noKFU3vo35JIxOOiOKetDOWtdEQH23f21jUPHAZI1Rsy6owd0cYSe_IhwlNbK80j1jJpXI8q1WmINVNO_LZmUCdPl1DUCpyEzf4wE8b2nH6xx87Hm_itR6uk7gWnsUaepPSMrxGXY0f.qoh80duyy39SQSmVtKF8_aMIGEQswpeydBXAzWC3N2nEF9JQwsd6z.jQMS5A_Ja403DFJPHh2duT4HQKehIcDlFfqtvx4BxDP3rUuUQ9KLv_WEyRLMw3EMJUWKbgdR.Fr4kTEV1RlLcvcOcux5.5Si1z22V5EuqdiNV49SIo0WPUSQeQxslI18kUwgKdig5HIQ1ZVHdXHAVq._HrYT6ujqKXRD9cOh60T8aMAxjqXowJL.mKLigeBF.WGf2iUp_arPJEwLSjT.Q99u8E2Y8DqN1y454ZTR9W5g92aOkuJfUjIaVcxByRb5s1_gCm1BYd3p0ywpBMXFwobbNVbTBPsDvLIbeCh.eoSHLnXzOdO1t4gcbNViN0Jsp9Nmtxk1kufdsFSIxtZ6ITbwN11Prl5lDTIOgGcbOCQlZNMAlo2T1jyCUNc35V9OC1RCBGCi4C5Ko8wMpBJ9.p6aCBOa0T.EJ78VoE9sXq.ylpIeb0RbseeV092013G6skYlQgsg2ed_hp3AnQQ4AAB7Ml3KuS3M1xWShLaiHysSjad.YmyO.da6i0k2Nl2oOPXEQZPV3iKklYwCEb4ME6546_Zg7cvCJpZhiDTngRAAHuq4kq8mXNG5uCn0SvmfYALY857Yuy.Aorp5osSnVXeedz7cdofPeQ.ZfQYHzvy3Z0aouRFite.AvncJz3Iqs81d0kOQyXNgTuSAR0GEBUHIX5yKjCeVqvBUSfF9MSSqWTu57_tvaUuLTpfB9zkufBZ.CHZHe2.Se.abkFGtgGHiaCqP9SPSGgK1QgWjLPVTyDSHChkLwOi.kiDy2FY2zjuc7mH9OSJE4BmfnE4Q3jZI6WD5sET1P4C1UxWvYRMk84i0xZb.m16XZ7pegxpAc1yQFdeLg9RsjAjCTuGbnobHhgpe0n4aYFC_G9p0bXoE5B9_F.Gwklag.6PP7Tk9aK8zmnqIBweBjUPUeFWSH_b4DuSFb97K6IpFGgcYHScDD7LVbmo.CvtWf9oKdIviQvbsMOZzAyGwNUKrjxazdqx4kjJQyztlPbK84DYU8NRRd9AqLw"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=92e751b48c06ce3d';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=in%3A145099&__cf_chl_rt_tk=XjdkVycYWbo0CBxIi_H9VVlv8DFCJ7Uj7_4nUjjUug0-1744341322-1.0.1.1-XiQkATaGVAwGSd_.40IgoKZm8Zh7whc7i5.X6scFztk" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>