7 citations · 24 across the 16 of their papers we have counts for
17 papers
Subexpressions and the Bruhat order for double cosets
Ben Elias, Hankyung Ko, Nicolas Libedinsky +1
The Bruhat order on a Coxeter group is often described by examining subexpressions of a reduced expression. We prove that an analogous description applies to the Bruhat order on do…
Demazure operators for double cosets
Ben Elias, Hankyung Ko, Nicolas Libedinsky +1
For any Coxeter system, and any double coset for two standard parabolic subgroups, we introduce a Demazure operator. These operators form a basis for morphism spaces in a category…
Graded extensions of Verma modules
Hankyung Ko, Volodymyr Mazorchuk
In this paper, we investigate extensions between graded Verma modules in the BGG category . In particular, we determine exactly which information about extensions betw…
On first extensions in -subcategories of
Hankyung Ko, Volodymyr Mazorchuk
We compute the first extension group from a simple object to a proper standard object and, in some cases, the first extension group from a simple object to a standard object in the…
Join operation for the Bruhat order and Verma modules
Hankyung Ko, Volodymyr Mazorchuk, Rafael Mrđen
We observe that the join operation for the Bruhat order on a Weyl group agrees with the intersections of Verma modules in type . The statement is not true in other types, and we…
Alternating sign matrices and Verma modules
Hankyung Ko
We show that the poset of alternating sign matrices, with Bruhat order, is isomorphic to the poset of certain submodules of the dominant Verma module for the special linear Lie alg…
A singular Coxeter presentation
Ben Elias, Hankyung Ko
We enlarge a Coxeter group into a category, with one object for each finite parabolic subgroup, encoding the combinatorics of double cosets. This category, the singular Coxeter mon…
Some homological properties of category , VI
Hankyung Ko, Volodymyr Mazorchuk, Rafael Mrđen
This paper explores various homological regularity phenomena (in the sense of Auslander) in category and its several variations and generalizations. Additionally, we…
Bigrassmannian permutations and Verma modules
Hankyung Ko, Volodymyr Mazorchuk, Rafael Mrđen
We show that bigrassmannian permutations determine the socle of the cokernel of an inclusion of Verma modules in type . All such socular constituents turn out to be indexed by W…
Some homological properties of category , V
Hankyung Ko, Volodymyr Mazorchuk, Rafael Mrđen
We compute projective dimension of translated simple modules in the regular block of the BGG category in terms of Kazhdan-Lusztig combinatorics. This allows us to det…
Adjunction in the absence of identity
Hankyung Ko, Volodymyr Mazorchuk, Xiaoting Zhang
We develop a bicategorical setup in which one can speak about adjoint 1-morphisms even in the absence of genuine identity 1-morphisms. We also investigate which part of 2-represent…
Polynomial functors and two-parameter quantum symmetric pairs
Valentin Buciumas, Hankyung Ko
We develop a theory of two-parameter quantum polynomial functors. Similar to how (strict) polynomial functors give a new interpretation of polynomial representations of the general…
2-representations of small quotients of Soergel bimodules in infinite types
Hankyung Ko, Volodymyr Mazorchuk
We determine for which Coxeter types the associated small quotient of the -category of Soergel bimodules is finitary and, for such a small quotient, classify the simple transiti…
Grade zero part of forced graded algebras
Hankyung Ko
The paper concerns a certain subcategory of the category of representations for a semisimple algebraic group in characteristic , which arise from the semisimple modules for…
Quantum polynomial functors from -Hecke pairs
Valentin Buciumas, Hankyung Ko
We define a new category of quantum polynomial functors extending the quantum polynomials introduced by Hong and Yacobi. We show that our category has many properties of the catego…
On modules arising from quantum groups at -th roots of unity
Hankyung Ko
This paper studies the "reduction mod " method, which constructs large classes of representations for a semisimple algebraic group from representations for the corresponding…
Cohomology in singular blocks for a quantum group at a root of unity
Hankyung Ko
Let be a Lusztig quantum enveloping algebra associated to a complex semisimple Lie algebra and a root of unity . When are irreducible -modules ha…