75 citations · 305 across the 41 of their papers we have counts for
6 papers · 1 filter
The Real Vanishing Ideals of Nuclear p-Norm Balls
Ghislain Fourier, Yuhuai Zhou
We study the algebraic and geometric structure related to tensor nuclear norms. We show that the unit ball of the nuclear norm is the convex hull of an irreducible real variety and…
Linear degenerations of flag varieties: partial flags, defining equations, and group actions
Giovanni Cerulli Irelli, Xin Fang, Evgeny Feigin +2
We continue, generalize and expand our study of linear degenerations of flag varieties from [G. Cerulli Irelli, X. Fang, E. Feigin, G. Fourier, M. Reineke, Math. Z. 287 (2017), no.…
On toric degenerations of flag varieties
Xin Fang, Ghislain Fourier, Peter Littelmann
Following the historical track in pursuing -equivariant flat toric degenerations of flag varieties and spherical varieties, we explain how powerful tools in algebraic geometry a…
Linear degenerations of flag varieties
Giovanni Cerulli Irelli, Xin Fang, Evgeny Feigin +2
Linear degenerate flag varieties are degenerations of flag varieties as quiver Grassmannians. For type A flag varieties, we obtain characterizations of flatness, irreducibility and…
Essential bases and toric degenerations arising from birational sequences
Xin Fang, Ghislain Fourier, Peter Littelmann
We present a new approach to construct -equivariant flat toric degenerations of flag varieties and spherical varieties, combining ideas coming from the theory of Newton-Okounkov…
Favourable modules: Filtrations, polytopes, Newton-Okounkov bodies and flat degenerations
Evgeny Feigin, Ghislain Fourier, Peter Littelmann
We introduce the notion of a favourable module for a complex unipotent algebraic group, whose properties are governed by the combinatorics of an associated polytope. We describe tw…