## September 2019

### Josh Kiers – A survey of the BGG description of cohomology of flag varieties, with applications, Part 4 – Advanced GMA Seminar

Part 4: A survey of the BGG description of cohomology of flag varieties, with applications Abstract: In these lectures we will follow the original paper of Bernstein, Gel'fand, and Gel'fand (Schubert cells and cohomology of the spaces G/P) which identifies the cohomology of flag varieties W-equivariantly with certain (sub)quotients of explicit polynomial rings. We will develop the Lie combinatorics necessary to identify (and prove) "good" polynomial representatives with their Schubert class counterparts, along the way introducing the Bruhat order and the famous…

Find out more »## January 2020

### Annalaura Stingo, UC Davis – Analysis & PDE Seminar

Title: Almost global well-posedness for quadratic quasilinear 2D wave-Klein-Gordon systems with small and localized initial data. Abstract: In this talk we will discuss our recent result on the almost global existence of small solutions of strongly coupled wave-Klein-Gordon systems (WKG) in 2+1 space-time dimensions. The coupling we consider is quadratic, quasilinear, and satisfies the so-called null condition. No restriction is made on the support of the initial data, that are small and only mildly decaying at infinity. Wave-Klein-Gordon systems arise from physical models especially…

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