2011/05/03 by H. W. Becker, Becker, Hanno · 1 citation
Computer Science · Mathematics · #Algebraic structures and combinatorial models #Commutative Algebra (math.AC) #FOS: Mathematics #Homotopy and Cohomology in Algebraic Topology #Representation Theory (math.RT) #Topological and Geometric Data Analysis
paper · pdf · doi:10.48550/arxiv.1105.0702
openalex publication_date 2011/05/03 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
This is the author's diploma thesis. We describe a simplification in the construction of Khovanov-Rozansky's categorification of quantum sl(n) link homology using the theory of maximal Cohen-Macaulay modules over hypersurface singularities and the combinatorics of Soergel bimodules. More precisely, we show that the matrix factorizations associated to basic MOY-graphs equal Cohen-Macaulay approximations of certain Soergel bimodules, and prove that taking Cohen-Macaulay approximation commutes with tensor products as long as the MOY-graph under consideration does not possess oriented cycles. It follows that the matrix factorization associated to a MOY-braid equals the Cohen-Macaulay approximation of the Soergel bimodule corresponding to the endofunctor on BGG-category O associated to the braid by Mazorchuk and Stroppel. This reduces certain computations in the category of matrix factorizations to known combinatorics of the Hecke-algebra. Finally, we describe braid closure as some kind of Hochschild cohomology and prove that the indecomposable Soergel bimodules corresponding to Young tableaux with more than n rows have trivial Cohen-Macaulay approximation, in analogy to the fact that the corresponding projective functors on category O vanish on restriction to parabolics with at most n parts.