主講人：張然 吉林大學(xué)教授

時(shí)間：2022年5月27日15：00

地點(diǎn)：騰訊會(huì)議 554 959 652

舉辦單位：數(shù)理學(xué)院

主講人介紹：張然，教授、博士生導(dǎo)師。1999年本科畢業(yè)于吉林大學(xué)數(shù)學(xué)系，2004年獲得吉林大學(xué)計(jì)算數(shù)學(xué)博士學(xué)位。現(xiàn)任吉林大學(xué)數(shù)學(xué)學(xué)院黨委書(shū)記、院長(zhǎng)，吉林國(guó)家應(yīng)用數(shù)學(xué)中心主任，吉林省運(yùn)籌學(xué)會(huì)理事長(zhǎng)等職務(wù)。主要從事非標(biāo)準(zhǔn)有限元方法及相關(guān)軟件平臺(tái)的開(kāi)發(fā)等研究工作，在包括計(jì)算數(shù)學(xué)領(lǐng)域的重要期刊《SIAM J Numerical Analysis》、《Mathematics of Computation》、《SIAM J Scientific Computing》等上發(fā)表學(xué)術(shù)論文60余篇。主持及完成基金委重大研究計(jì)劃重點(diǎn)項(xiàng)目等7項(xiàng)國(guó)家級(jí)項(xiàng)目，擔(dān)任AMC、DCDS-B、CMR等期刊編委。

內(nèi)容介紹：This talk is devoted to studying eigenvalue problem by the weak Galerkin (WG) finite element method with an emphasis on obtaining lower bounds. The WG method uses discontinuous polynomials on polygonal or polyhedral finite element partitions. As such it is more robust and flexible in solving eigenvalue problems since it finds eigenvalue as a min-max of Rayleigh quotient in a larger finite element space. We demonstrate that the WG methods can achieve arbitrary high order convergence. This is in contrast with classical nonconforming finite element methods which can only provide the lower bound approximation by linear elements with only the second order convergence. We also presented the guaranteed lower bound for k=1 order polynomials and some acceleration techniques are applied to WG method.