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We study the quiver of the descent algebra of a finite Coxeter group W. The results include a derivation of the quiver of the descent algebra of types A and B. Our approach is to study the descent algebra as an algebra constructed from the…

Representation Theory · Mathematics 2008-07-09 Franco V. Saliola

We follow the dual approach to Coxeter systems and show for Weyl groups a criterium which decides whether a set of reflections is generating the group depending on the root and the coroot lattice. Further we study special generating sets…

Group Theory · Mathematics 2019-05-01 Barbara Baumeister , Patrick Wegener

We give a uniform geometric realization for the cluster algebra of an arbitrary finite type with principal coefficients at an arbitrary acyclic seed. This algebra is realized as the coordinate ring of a certain reduced double Bruhat cell in…

Rings and Algebras · Mathematics 2008-05-19 Shih-Wei Yang , Andrei Zelevinsky

Cluster-tilted algebras are trivial extensions of tilted algebras. This correspondence induces a surjective map from tilted algebras to cluster-tilted algebras. If B is a cluster-tilted algebra, we use the fibre of B under this map to study…

Representation Theory · Mathematics 2009-12-03 Ibrahim Assem , Thomas Bruestle , Ralf Schiffler

We classify the twisted tensor products of a finite set algebra with a two elements set algebra using colored quivers obtained through considerations analogous to Ore extensions. This provides also a classification of entwining structures…

Rings and Algebras · Mathematics 2007-06-17 Claude Cibils

We show that for cluster algebras associated with finite quivers without oriented cycles (with no coefficients), a seed is determined by its cluster, as conjectured by Fomin and Zelevinsky.We also obtain an interpretation of the monomial in…

Representation Theory · Mathematics 2020-12-21 Aslak Bakke Buan , Bethany Marsh , Idun Reiten , Gordana Todorov

In a recent paper, Barot and Marsh presented an explicit construction of presentation of a finite Weyl group by any seed of corresponding cluster algebra, i.e. by any diagram mutation-equivalent to an orientation of a Dynkin diagram with…

Combinatorics · Mathematics 2019-10-25 Anna Felikson , Pavel Tumarkin

We introduce Coxeter-sortable elements of a Coxeter group W. For finite W, we give bijective proofs that Coxeter-sortable elements are equinumerous with clusters and with noncrossing partitions. We characterize Coxeter-sortable elements in…

Combinatorics · Mathematics 2026-05-13 Nathan Reading

Let $\A$ be a finitary hereditary abelian category and $D(\A)$ be its reduced Drinfeld double Hall algebra. By giving explicit formulas in $D(\A)$ for left and right mutations, we show that the subalgebras of $D(\A)$ generated by…

Representation Theory · Mathematics 2017-01-10 Shiquan Ruan , Haicheng Zhang

We consider the finite Weyl groups of classical type -- $W(A_{r})$ for $r \geq 1$, $W(B_{r}) = W(C_{r})$ for $r \geq 2$, and $W(D_{r})$ for $r \geq 4$ -- as supergroups in which the reflections are of odd superdegree. Viewing the…

Representation Theory · Mathematics 2026-04-14 Christopher M. Drupieski , Jonathan R. Kujawa

We provide a complete classification of the singularities of cluster algebras of finite cluster type. This extends our previous work about the case of trivial coefficients. Additionally, we classify the singularities of cluster algebras for…

Algebraic Geometry · Mathematics 2025-09-23 Angélica Benito , Eleonore Faber , Hussein Mourtada , Bernd Schober

Exceptional sequences are certain ordered sequences of quiver representations. We use noncrossing edge-labeled trees in a disk with boundary vertices (expanding on T. Araya's work) to classify exceptional sequences of representations of Q,…

Representation Theory · Mathematics 2014-12-11 Alexander Garver , Jacob P. Matherne

We introduce a category of cluster algebras with fixed initial seeds. This category has countable coproducts, which can be constructed combinatorially, but no products. We characterise isomorphisms and monomorphisms in this category and…

Representation Theory · Mathematics 2012-01-31 Ibrahim Assem , Grégoire Dupont , Ralf Schiffler

We give a criterion for a finitely generated odd-angled Coxeter group to have a proper finite index subgroup generated by reflections. The answer is given in terms of the least prime divisors of the exponents of the Coxeter relations.

Group Theory · Mathematics 2019-10-25 Anna Felikson , Jessica Fintzen , Pavel Tumarkin

We classify all tilting and cotilting classes over commutative noetherian rings in terms of descending sequences of specialization closed subsets of the Zariski spectrum. Consequently, all resolving subcategories of finitely generated…

Commutative Algebra · Mathematics 2014-06-03 Lidia Angeleri Hügel , David Pospisil , Jan Stovicek , Jan Trlifaj

We prove triviality of the centre of arbitrary Hecke algebras of irreducible non-finite non-affine type. This result is obtained as a consequence of the following structure result for conjugacy classes of the underlying Coxeter groups. If…

Group Theory · Mathematics 2024-02-23 Timothée Marquis , Sven Raum

We introduce the notions of $\tau$-exceptional and signed $\tau$-exceptional sequences for any finite dimensional algebra. We prove that for a fixed algebra of rank $n$, and for any positive integer $t \leq n$, there is a bijection between…

Representation Theory · Mathematics 2021-06-04 Aslak Bakke Buan , Bethany Marsh

We show that the irreducible representation of the asymptotic Hecke algebra corresponding to a special representation of a Weyl group admits a basis with strong positivity properties.

Representation Theory · Mathematics 2016-02-24 G. Lusztig

In this paper, we obtain relations in the Weyl groups of Kac-Moody algebras that come from mutation classes of skew-symmetrizable matrices. These relations generalize those obtained by Barot and Marsh for finite type. As an application, we…

Combinatorics · Mathematics 2014-04-04 Ahmet Seven

The blob algebra is a finite-dimensional quotient of the Hecke algebra of type $B$ which is almost always quasi-hereditary. We construct the indecomposable tilting modules for the blob algebra over a field of characteristic $0$ in the…

Representation Theory · Mathematics 2019-09-11 Amit Hazi , Paul Martin , Alison Parker