Categoria:
Altro (categoria non censita)
Categoria non censita:
Algebra & Representation Theory Seminar (ARTS)
Data e ora inizio evento:
Data e ora fine evento:
Aula:
Altro (Aula esterna al Dipartimento)
Sede:
Dipartimento di Matematica, Roma Tor Vergata
Aula esterna:
Aula Dal Passo
Speaker:
Allen Knutson (Cornell)
There is a beautiful "positroid" stratification of the Grassmannian,
studied by Lusztig, Postnkov, Rietsch, Williams, K-Lam-Speyer, and many
others (with strata most naturally indexed by juggling patterns). We gave a formula representing the class of a positroid variety, which Fan-Guo-Su-Xiong (FGSX) recently expressed as a sum over "periodic pipe dreams". In this talk I'll explain all that, and introduce "matrix positroid varieties", which are what the FGSX formula is really for.
Time permitting, I'll explain the necessary upgrades for Chern-Schwartz-MacPherson classes. This work is joint with Paul Zinn-Justin.