13 citations · 33 across the 8 of their papers we have counts for
8 papers
Vanishing cotangent cohomology for Plücker algebras
Jan Arthur Christophersen, Nathan Owen Ilten
We use representation theory and Bott's theorem to show vanishing of higher cotangent cohomology modules for the homogeneous coordinate ring of Grassmannians in the Plücker embeddi…
Comparison theorems for deformation functors via invariant theory
Jan Arthur Christophersen, Jan O. Kleppe
We compare deformations of algebras to deformations of schemes in the setting of invariant theory. Our results generalize comparison theorems of Schlessinger and the second author…
Hilbert Schemes and Toric Degenerations for Low Degree Fano Threefolds
Jan Arthur Christophersen, Nathan Owen Ilten
For fixed degree , we study the Hilbert scheme of degree smooth Fano threefolds in their anticanonical embeddings. We use this to classify all possible degenerations…
Degenerations to Unobstructed Fano Stanley-Reisner Schemes
Jan Arthur Christophersen, Nathan Owen Ilten
We construct degenerations of Mukai varieties and linear sections thereof to special unobstructed Fano Stanley-Reisner schemes corresponding to convex deltahedra. This can be used…
Deformations of equivelar Stanley-Reisner abelian surfaces
Jan Arthur Christophersen
The versal deformation of Stanley-Reisner schemes associated to equivelar triangulations of the torus is studied. The deformation space is defined by binomials and there is a toric…
Deforming Stanley-Reisner schemes
Klaus Altmann, Jan Arthur Christophersen
We study the deformation theory of projective Stanley-Reisner schemes associated to combinatorial manifolds. We achieve detailed descriptions of first order deformations and obstru…
Cotangent cohomology of Stanley-Reisner rings
Klaus Altmann, Jan Arthur Christophersen
Simplicial complexes X provide commutative rings A(X) via the Stanley-Reisner construction. We calculated the cotangent cohomology, i.e., T1 and T2 of A(X) in terms of X. These mod…
On infinitesimal deformations and obstructions for rational surface singularities
Jan Arthur Christophersen, Trond Stoelen Gustavsen
The purpose of this paper is to prove dimension formulas for and for rational surface singularities. These modules play an important role in the deformation theory of i…