• Deformations of modules of maximal grade and the Hilbert scheme at determinantal schemes 

      Kleppe, Jan Oddvar (Journal of Algebra;407, Journal article; Peer reviewed, 2014-04-04)
      Let R be a polynomial ring and M a finitely generated graded R-module of maximal grade (which means that the ideal I_t(\cA) generated by the maximal minors of a homogeneous presentation matrix, \cA, of M has maximal ...
    • The Dirac operator on compact quantum groups 

      Neshveyev, Sergey; Tuset, Lars (Journal für die reine und angewandte Mathematik;2010 (641), Journal article; Peer reviewed, 2010-01-20)
      For the q-deformation Gq, 0 < q < 1, of any simply connected simple compact Lie group G we construct an equivariant spectral triple which is an isospectral deformation of that defined by the Dirac operator D on G. Our ...
    • Families of Artinian and one-dimensional algebras 

      Kleppe, Jan Oddvar (Journal of Algebra;311, Journal article; Peer reviewed, 2007)
      The purpose of this paper is to study families of Artinian or one dimensional quotients of a polynomial ring R with a special look to level algebras. Let GradAlg^H(R) be the scheme parametrizing graded quotients of R with ...
    • Families of Determinantal Schemes 

      Kleppe, Jan Oddvar; Miro-Roig, Rosa Maria (Proceedings of the American Mathematical Society;, Journal article; Peer reviewed, 2011-03-16)
      Given integers a_0 <= a_1 <= ... <= a_{t+c-2} and b_1 <= ... <= b_t, we denote by W(b;a) \subset Hilb^p(P^n) the locus of good determinantal schemes X in P^n of codimension c defined by the maximal minors of a t x (t+c-1) ...
    • Families of low dimensional determinantal schemes 

      Kleppe, Jan Oddvar (Journal of Pure and Applied Algebra;215 (7), Journal article; Peer reviewed, 2010-11-09)
      A scheme X in P^n of codimension c is called standard determinantal if its homogeneous saturated ideal can be generated by the t x t minors of a homogeneous t x (t+c-1) matrix (f_{ij}). Given integers a_0 <= a_1 <= ... <= ...
    • Ideals generated by submaximal minors 

      Kleppe, Jan Oddvar; Miro-Roig, Rosa Maria (Algebra & Number Theory;3 (4), Journal article; Peer reviewed, 2009)
      The goal of this paper is to study irreducible families W(b;a) of codimension 4, arithmetically Gorenstein schemes X of P^n defined by the submaximal minors of a t x t matrix A whose entries are homogeneous forms of degree ...
    • Liaison invariants and the Hilbert scheme of codimension 2 subschemes in P^{n+2} 

      Kleppe, Jan Oddvar (Progress in Mathematics;Vol. 280, Chapter; Peer reviewed, 2010)
      In this paper we study the Hilbert scheme, Hilb(P), of equidimensional locally Cohen-Macaulay codimension 2 subschemes, with a special look to surfaces in P^4 and 3-folds in P^5, and the Hilbert scheme stratification H_c ...
    • Moduli Spaces of Reflexive Sheaves of Rank 2 

      Kleppe, Jan Oddvar (Canadian Journal of Mathematics;62 (5), Journal article; Peer reviewed, 2010)
      Let F be a coherent rank 2 sheaf on a scheme Y in P^n of dimension at least two. In this paper we study the relationship between the functor which deforms a pair (F,s), s in H^0(F), and the functor which deforms the ...
    • Notes on the Kazhdan-Lusztig Theorem on Equivalence of the Drinfeld Category and the Category of U(q)g-Modules 

      Neshveyev, Sergey; Tuset, Lars (Algebras and Representation Theory;14 (5), Journal article; Peer reviewed, 2011)
    • Quantization of subgroups of the affine group 

      Tuset, Lars; Bieliavsky, Pierre; Gayral, Victor; Neshveyev, Sergey (Journal of Functional Analysis;Volume 280, Issue 4, 108844, Journal article; Peer reviewed, 2021-02-15)
      Consider a locally compact group such that V is abelian and the action of Q on the dual abelian group has a free orbit of full measure. We show that such a group G can be quantized in three equivalent ways: (1) by ...
    • Unobstructedness and dimension of families of codimension 3 ACM algebras 

      Kleppe, Jan Oddvar; Miro-Roig, Rosa Maria (Contemporary Mathematics;448, Journal article; Peer reviewed, 2007)
      The goal of this paper is to study irreducible families of codimension 3, Cohen-Macaulay quotients A of a polynomial ring R=k[x_0,x_1,...,x_n]; mainly, we study families of graded Cohen-Macaulay quotients A of codimension ...
    • Unobstructedness and dimension of families of Gorenstein algebras 

      Kleppe, Jan Oddvar (Collectanea Mathematica; 58(2), Journal article; Peer reviewed, 2007)
      The goal of this paper is to develop tools to study maximal families of Gorenstein quotients A of a polynomial ring R. We prove a very general Theorem on deformations of the homogeneous coordinate ring of a scheme Proj A ...