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: '92d625ae59a3fe8b',cH: 'ulF.Oa26Bsso.Fgzx.IHyjhPG91d6keHbCZP_gQbiPc-1744161261-1.2.1.1-NKQzKxNZVuowDl7pI9xoIv9Rk37ITA0ZfJJ3Az0PAAQyRqLjOZv5HnnycVMv8Aor',cUPMDTk: "\/?q=in%3A409787&__cf_chl_tk=aaRTYkQ_g0PFqEuVwi.V1uYsQMab0aW7BEFZXf5ZZoA-1744161261-1.0.1.1-OSEW11FvVoCna5k_mFEt4N.4SZEzEP16eU8cgc.38M0",cFPWv: 'g',cITimeS: '1744161261',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/?q=in%3A409787&__cf_chl_f_tk=aaRTYkQ_g0PFqEuVwi.V1uYsQMab0aW7BEFZXf5ZZoA-1744161261-1.0.1.1-OSEW11FvVoCna5k_mFEt4N.4SZEzEP16eU8cgc.38M0",md: "vTEc6VWolyKZSzP4hSwLq8tLCOR.K6UqzGKziPm_QRE-1744161261-1.2.1.1-mgIP_lFn.n2TTzrj8lFdjvJHdfUZOimahMlTb6x59IgTUEOuOZdX5.WhS5hbsDtAbAzCd4PTrXqveuHDnn0ikxbDR2HqcI8Noy_gykjV3CxWA2sV6F5JcWpPErkGnz.oy25mgaj4iWRoYqZG5uh_LHXu.7TU39mXZCBN914ZGYr_MZJi_vhkGUn_wRbr0ql8S7LSARQQfyS3Br6xCD8xMxnywcIGd94LSlwHkLR5wXdHPOEL3uYa.lXSho.NW1572AI19zy1xqSCsHE2SjRUWcON.E0q0sWr.bKyDQzlWht6McdBm0WYr63Tla.8eroe922NMM6W.7O5oGBMdYuBzYXAuGZcCPROgAERayg1UMEP.NwDhIxnGwDly4o0vsZAt3a_aPPpsD26PGnAP.ZTgVllJCd03k5D.y8VLsKXVFQNuW3Wc.tf_.ujqzdyl6D7RaheIXXTLuQZ4JWm5hMZ318LsFeZtVzClL6Cy4TYfnkmCTw2nZaKTiksHvOOAFh3V_hEF14rCgzR4rW9zGwW13aycFppSL4JRIGiL4gTEI5FEFYHGE_nqSx8DJpcKkizB5Vl08UrK8jr3In7gG9S1NskodUtLHF33fm9.3PrX3STeFWieIvQ48nwWqEY3Ksi9itWbx51Tke3dzyEmft.GB84O9kVtcfiiz1E0Z3ubs9anPof3fG7LOZRagBL_Ztn9EJuuJP0cfat2NlStBZ2TD29b6TOZjiOLbAuH5YBOnKPOIl3KIqu53xLouWI0ibx9YfRKa8a.00jjnYhoPBqXIuZi3vNKYtmFWnWhudrKzibNQCtCj.NlEo09g.udqCz0grhUow6x5OGWNy5gua.fRUI96VUjxrevmkQGwo.yRfrGnTdmNEmgqll_y3HoZD14CcYZa.0A_jYwXKe9AjlDiLsEfldiPjr408B7SrYYr9iEA3xONPAEfhpXfHZuKkIN4uPWz_JHGV6Gs3zdm4nwf31givbIyC_FV53fZIGUS67SuzJhLFMYSBmRCib.A7MCGuzwrvxsT4MjCySfCUq5hUOiRktygFyTqtBBtRuZFSD_EPHZvTAckLxnbgBZ.M0wjMIFUO8.VD12TScApRX8JrB4YInro5.powo5ZFSnEKj_2.Jgy34WaCMG094zktGjRPiqwiwyLaXUnpGXpvWKqn14V3Y3AM_Aif004kGiLTv.6KL8B.UxnmSNLQNKyqG",mdrd: "XL8ZprWU9RlIOS7eg0LSYIixXm4xgyk1Of1LZSKXi1M-1744161261-1.2.1.1-Y4B.0SKTDddlxKapJ7E08c3E_mxenCfC.7h8cLeTNu0jMYiNVqwPa1zGMNEDloYW_ySfCzMMM1d569h1WGc30DoB4N3TrJfMB2jq6tlBwXb_dZaN6uw9wJXQcLed.widI1j1OuxYZsy9g8n7ffmjzf2XMh1m24EHp1Ak4P8M6_S5CkoT6qNAUHjS9etByeiLYcZoD8abc77rIzAPbnmODyxeF2pZZAEEra_x5MD3nucjrYbFEP_NJ0OlA6EnKn5JEp6cnnVt7wxYUPrwcTTcZ6zhreIuoB9P_pzf5W8EMJAYDcL_NbOhoXQh5upXvPFaEkvhJcO2rCWw0bvxa.S5DrvackncpeD5DqVIpJsrukjO0Kb3qFlGrhbS2rVoGgjeckYOgsH9QrWJPH.rGYpEpd5jT9LTMlqCOhubQXZNpBNLGGIvM87O3mouYwlEeC45POK8uvrg3Xz5OKHdZRX3dZ_p4DfvPlI6NMUbUyUyBYcAwAXjFzltewuibLg6ijEMksLHnAbZE0ciqHv_WVFRrqoEyfb1qrXx_JT3dwPEivx8asCIKNnU.7mLIUlMfHLqGKGUu_tM7HvSZqVVjmouc37wFW93cB8TkIE4CdoRNY2JC2fWmK92eKBpQjZn1XKG2IN6Qkbvhn.d9Eux3UVxypEOM9xAAKx2P5usm17XkWm4zWziOyI1nz9_WIVL10EHhjHkPtfxN4nKFjtk57Ghs7g.zEcOtlv4T_eHFar68Kjn2AoMmo7PB4qo11X8ShbcAuabHDHoYQKooB4ij97paUqKmJ124E8T6uPWjgAg5ekcCYwjHBlx0UZ5mCsclObPd5TlR1rmKPTG6KSGThrqvNniR8IysAlIjwtoN9matPikjU.KjcObNaVPNa2MB1YJgp6zr16cS5VHKHA4ThTLr4bzdoc0cUvpcLuF.yjFM6c9u78EGeKOwJEbEr.reJsD5I6znDpYgWuqnRiTTpTFSYUxHxTC8.33OuoyVLCGpsjL02SA9c5fo5sGpLe5dsbAk1E3r4xpR1m0j_zCNujUcxkmIyS3fRBm5X9DLi86QG4aLe1_.Kz9YrB2Sn8C0fLO_85eFN6p_kbkB5ztffXzuAf1tr8fPXjYyQ4bvH8yLywHdIPtl35P2uaBgSZdIwT72ZeoTm6PMkF9RvLjWPDcoFwT8SpisKvznjKrmuzptVFq6MG6loYBDODhvl4kBw1fDKxJN.Kq_YW8cfxyyG9diltc8PURXr3bbFe5NjLeoXubtrQ.o.1z2JsYmiUy.5JtTjj8iRNhLcuDInLHlshjyG.fDmXHxrDn45obN69VWfeywJbVmnpq5Dv8oslkaCyo0fvrjBuLEFVU64Oe_e24c_9dpJHdDq23QqRVP45i3pF3V.oZGarrZ82rUosVDkFD.4eHZVGVgdsgKR1R84x2U82cr.sE5l24Eb_dzX1m4ViXjZEtYOcpXnwVALrK1ynFiB4mbQ8mEMIdh205RSJIgFPhivxi1PHpAJdpa04yOoY5MslwDCIp9tNwzZhBR4ACr5XkXE0G.Utuq6TIDTq8PfaAg2TK4aNYQn06hjCrYmTK_UmL.eWvy84YpHZA62qbu.547Nn_t2wu7YAv2kib0rDZecPOVNkeVXSrtjCyn7xWusJ_wxu_AGPO1l3WBESMWJm0a0BaOSrW.iHcyy7xV5dZGUQdq.hc5O_LeXO2mtkgkjJ2PNcNhUaDDE580uOgT9TbRQpnNYgj5H6Ubph4HhvQkKhVel1bxFn.nPH_8MIzsjlaPi.1Mt0N5s3sZrJ7_hcGw3yEsqe4WLmdXLNhGJg2ihyAJpyUaoLtVNWg886CKUsvXU9f8a2ZbP9V6Qgm4k0KHKL8ObKfAOBaX7D8m9hOKsUbvBUActGwBnxR78B9ejm7SWrnmGAIQXOPMmnomPAW.afNfSK3y5bi4DNCTeQa5wtsxpcVOgSGDd7s5Wqno7GsWD3JCIYR7K0AZaAbz7TqJseHTh5uY45qEkt66TPHGGH1WuwAhpCH2mUmiZLaT5PRMAxnsq8WlsZkFb0zSq1DtTBDv.H4C.aKXt1h5Q"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d625ae59a3fe8b';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%3A409787&__cf_chl_rt_tk=aaRTYkQ_g0PFqEuVwi.V1uYsQMab0aW7BEFZXf5ZZoA-1744161261-1.0.1.1-OSEW11FvVoCna5k_mFEt4N.4SZEzEP16eU8cgc.38M0" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>