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: '92d6e81868429c1a',cH: 'dDV72mNIXA9QiMO4Sm8BrvEEcz9tOyjwDfefG01umYg-1744169225-1.2.1.1-FNbsrC3ys8kHc8Nn4ZQTIOvwoSL2o0OKEPual3uIOb1BDGX1YzDJHeNY3hNy9TCo',cUPMDTk: "\/1338.68037?__cf_chl_tk=v6HiF2odC7qD9N2sV6iPCOm2CEiw2lQ6jB6lEW2ozXE-1744169225-1.0.1.1-iCgYg5Og0erhM9WMsCiH5gVjG5xgTFxPc2.UBswUPmY",cFPWv: 'g',cITimeS: '1744169225',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "unsupported_browser_beacon",fa: "\/1338.68037?__cf_chl_f_tk=v6HiF2odC7qD9N2sV6iPCOm2CEiw2lQ6jB6lEW2ozXE-1744169225-1.0.1.1-iCgYg5Og0erhM9WMsCiH5gVjG5xgTFxPc2.UBswUPmY",md: "nhnJcTMN_UWj6CrKVCo3LTDy5MDpjJLKsBRIyOQfXZU-1744169225-1.2.1.1-CjQkeER2fmJAdWtQstVYxpgq_jZEWgqZ9nPYpn4xLDQEULnL5Mw6B68qP9AsSS2wN8ptCBC6cifKOve_sBVJm1I3_AB2DaPoiqqoYL_Jf4l.v0bzx9b248C2HuVdosiqi5_.7yb2i2G8SB9iuj1yS_vjeCGsCabsma_trIkLm8JZKpOdIsXX74wOLyUxEvshZc3YkfGNSalGqo9rOgkySAt2fuhEADEnUgbGRdsWtzf3MGrizP_HArUYh7PZztXhBvNPZzpRdJYYCTHaw5F1D3GNx1kIQamf1iNndagcZLmN3r_D5sJH.NnoMKLnVzLE2zniMhBGItSyrz7mun_RXHxxODf900BTgDl3CAElSJ5ydFu_ahxG3gMMI6oyhcWOwIXGVOveLK.Cvi_Qn0ASUzQ7pkuuj3nLjIz6kJNrcVT7uQJnYk5THlYrnUHw1St7ajE9ZXlcTgwExeSvIku_RYm.wQYRhpQAhlwC7Z.ZlDDN1LAUNIOChLrt1V.G__tSQ_krXNg8BslWslDy8Bjt1u_iaAiM.gidtUvCcP1gYwDtH.BkOLJVjkkMSuk6S0u.nSOjLb4kW9vXGJSfw_2.wtw6pmYEYpxWKn5qs6XbPZHkKr9SZ3ggpGA6gC3XVFSIDbkLmMyE0a5MAZpjdeJdHs788W5Ms6CDHFN_mAFLYwPTnrVczkoAKsR81TBZvLPz8Ts743TpAYYA54nj5.j.0bQ1AWUOu3aoi31Y4sP40sD1Lrs.3lLPD.SML39wPjcDSRy64AENQ80i.dxN4.fsQgwA.knuXcLjEqyCHgAlJ2n1Q3N4HV9kYShtJ9DgKCq_HuVre6.oIbfq8D5O1wBIzWvLZRGNluifXSPGs1JzIPtQu34JLy3nFMPkmtkaJlV8qvYggbfb25Toq7XG1enxAAFuA00xpsZJ4i.BWpzJ_IPfqHYq3ZGD7ayH1CqIHfzhqCB6UMNdB5GbbmKnOKJ7qA510xLKMQBiSkV_p2.dJkgnuf4tIIFFn6f_KqmX7.f1Y_3dNSIY_gZde8hDQ3DS5xw2t8V6JFfVUBMwKGhMlUgSeadfFls4IVdn4H8tRmMCWnA0HAJ_edWfEExk2RftXudWdU_mbiI9pcEtvqVUUL_5PzdoxiTHx7cSspt0wWwF1ybsQUKSQEiT4YP4SCtZrWkRRZZvoCykbu6ePiy8OOMEaAmC03.Ulvz1kQQDS01w",mdrd: "nAbhckCYBLNIVeM_Jp.p0HT1.2xQpcz5lz01W.pqswE-1744169225-1.2.1.1-JpviqhvtjEQZxXQN9GTOg86Hezid2FAxOa50_BY3gNytPvKZn14Aa8H4Ut3ieRQlzlhm9kXXwdujnHzIKNC00tN.Qo9O0r.rYaFj6ZotRDHN9fnFKI_W7J7tiYYjyxiO3OpdgWc_bCXPN0Z2GAkX4dgE5lQM.ywxbIzb4Edywkm3c6x00GcsgzaKMUeLA12ErJLKR.Jh2zxbb3MqhVWKjDyMCiQcQPeemgD04RzeyvalToF8Anh3YOMI1g848ONFq2M_HRWk0nTUV7CnMRaS_BgNXCy2J3rBm6rcz1YgNK7OBmBCWIq_0i6G5RoPTf2Jq10yqP_Mh6qKssfj_3dIm9knWdvfGW2oyvlplr.XmOiqk18plKyhNKycUO0cEafBYeTreGjiiMRL63uCMgIsd_tim7DkIxVUNmBnXmv5AAUK18FLEIEVFR4EC.hWyzhcgUXc4AP93ctmK.0Y.DAHHEKcBLkcdYBRMO3dVV56OkPFnCmGylRDDH17R6rGlDNWskklYwJdcM62mF5nP5WD9XKT4FqIdzuSUYn.Wa5gU0jogjJz7ecdLRJ49FGJXtDpk7QKTucWvOumBSmbiUSg5kfqx.XCnEi19Or4D1.u1gURZBkx95xB5eeBQGrpp_CbP0NQNR1brJbkHAFZvN_ZKvQQFsBQD2YFBy5r8s9UWwg5iMLb8GX6zquX3tC8aAjdxRZ0FA7Xuj1d3WW1zgJDvASGXaJd.Pn4.s.Q0gaCa3f1GfKx1PX77BLchX5bgMdNBd0nXkuFXA2DhefLkl7WgLsbtUshFC_oPPTvrcuwAzs0J5ZEjaHJUS_UuP4Heosdg091vrRi0C..UXpOdmOxHxZm4BGYKwMauxuSwmrAmmNKviAg9u1kz2rxmL9_LIncYzxah44O6DDGGUnKcElcUnKOwUTsiNmlKx76dK62lOcYuydQT9Va2ZgeGHb6bMM6Fykojw5jiVRLBr9FAMVRKf7f9uQiBqQAzbmEDrBXdJxQXwhM_SOpxgLSgilVUfd68w8Apt_vSRRuJxxBYZmZqZPbFgDx3KE7__xht.Oazo4H_J4Qm_zhzG17zqOlwS4vGisOwzexd_xPrfdGVZoafQ0L94ETAhfF6jyhHtTbpmdCdVkq8.ZNEniZ7ptBvjCUbUTwKV9iJn0K0D7jl9Me9mDFxlBosHn7BxYA7tMD6yFkIzp0NXBd6cpls0KuabI7S7TL.bd0RWlLVj02e4.yKGim6G9ZfcD5Tkw0Due6bdbHKz2TYnh5gwJkB3Zd3ush_woEgGhgdEAMTGyFNt2cCRQ_CH67pJkADH9umHvn0Je88Dvg6mOmtdmqN_u7uttefDhLcPOZBTAEpfrLPZmbZqyJ0UylQAIV5vThc4Eggf10GFUkNJQOpdjvQ2XJs_6lzDthxIq4HIn185kiKgyW7WVylLpTyQilsEAqUhi70zUi7Sbco3VJh6k1zrw_TuWXqprlo.02gjLaxaeFaNCteWxrTIkas8L1P6f_8D2VdPWxEvcqzr0V6CBaO1cUxPAcpMFYdLEPW8M6a9PSQV1c5.EExi7iLCsP5aCRQeUXfSfZHO83iWQB68heyWGR_OoIkB4KA8pLNEZhvE.t89e5GPOzJcUhv3efCtzap8rzm5FBv6pZXq9aLUPhXTswfLrGF4FKLeuCjeps_L1tIDasA08gbrgzOELjeMJkc8i0.pPrTh5Bz13hFsDFo7jdzy0_Xi_Lg1mGoBHbeNdErtz_NOwWkW3PF_f_og2ZJsTHkIWC0qJD8ecVIRWNCzNzNlJ.2DOlfFmwOLOEsAJQpzFtcD2e3oETSwIiAY_8wpxep7CYgnI8orHgAjOy0GHfJZxPoaNfsYfGQHW3WXVFm5H59khXTet7Ld3qbZcKOMIxPGpcXgMIdc_LbmvWAZBwvmriJ7ZXgZqkAlCdwWTcsuocDnTw7p.kFBakcg.uiB5LlK01zgyw9vhdqJBLAsy.sLCaBdmOLAV_0GgSuxvISbWUb5AFqk.NPyimDBO4ZeO9wfN5Qz6JkHQDlvFAMxFzoVk.4zZoSyAsxuMoqDHPo8vr3g"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=92d6e81868429c1a';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, "\/1338.68037?__cf_chl_rt_tk=v6HiF2odC7qD9N2sV6iPCOm2CEiw2lQ6jB6lEW2ozXE-1744169225-1.0.1.1-iCgYg5Og0erhM9WMsCiH5gVjG5xgTFxPc2.UBswUPmY" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>