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Pierre-Guy Plamondon

Publications and source records attributed to Pierre-Guy Plamondon.

28 records · Page 2Linked to original sources
arXiv2017

Cluster characters

These are lecture notes from a mini-course given at the CIMPA in Mar del Plata, Argentina, in March 2016. The aim of the course was to introduce cluster characters for 2-Calabi-Yau triangulated categories and present their main properties. The notes start with the theory of F-polynomials of modules over finite-dimensional algebras. Cluster categories are then introduced, before the more general setting of 2-Calabi-Yau triangulated categories with cluster-tilting objects is defined. Finally, cluster characters are presented, and their use in the categorification of cluster algebras is outlined.

math.RT↗
arXiv2016

Counting friezes in type D_n

We prove that there is an finite number of friezes in type D_n, and we provide a formula to count them. As a corollary, we obtain formulas to count the number of friezes in types B_n, C_n and G_2. We conjecture finiteness (and precise numbers) for other Dynkin types.

math.CO↗
arXiv2016

Derived invariants for surface cut algebras II: the punctured case

For each algebra of global dimension 2 arising from the quiver with potential associated to a triangulation of an unpunctured surface, Amiot-Grimeland have defined an integer-valued function on the first singular homology group of the surface, and have proved that two such algebras of global dimension 2 are derived equivalent precisely when there exists an automorphism of the surface that makes their associated functions coincide. In the present paper we generalize the constructions and results of Amiot-Grimeland to the setting of arbitrarily punctured surfaces. As an application, we show that there always is a derived equivalence between any two algebras of global dimension 2 arising from the quivers with potential of (valency at least 2) triangulations of arbitrarily punctured polygons. While in the unpunctured case the quiver with potential of any triangulation admits cuts yielding algebras of global dimension at most 2, in the case of punctured surfaces the QPs of some triangulations do not admit cuts, and even when they do, the global dimension of the corresponding degree-0 algebra may exceed 2. In this paper we give a combinatorial characterization of each of these two situations.

math.RT↗
arXiv2016

SL_2-Tilings Do Not Exist in Higher Dimensions (mostly)

We define a family of generalizations of $\operatorname{SL}_2$-tilings to higher dimensions called $\boldsymbolε$-$\operatorname{SL}_2$-tilings. We show that, in each dimension 3 or greater, $\boldsymbolε$-$\operatorname{SL}_2$-tilings exist only for certain choices of $\boldsymbolε$. In the case that they exist, we show that they are essentially unique and have a concrete description in terms of odd Fibonacci numbers.

math.CO↗
arXiv2013

Nakajima varieties and repetitive algebras

We realize certain graded Nakajima varieties of finite Dynkin type as orbit closures of repetitive algebras of Dynkin quivers. As an application, we obtain that the perverse sheaves introduced by Nakajima for describing irreducible characters of quantum loop algebras are isomorphic to the intersection cohomology sheaves of these orbit closures.

math.QA↗
arXiv2012

Generic bases for cluster algebras from the cluster category

Inspired by recent work of Geiss-Leclerc-Schroer, we use Hom-finite cluster categories to give a good candidate set for a basis of (upper) cluster algebras with coefficients arising from quivers. This set consists of generic values taken by the cluster character on objects having the same index. If the matrix associated to the quiver is of full rank, then we prove that the elements in this set are linearly independent. If the cluster algebra arises from the setting of Geiss-Leclerc-Schroer, then we obtain the basis found by these authors. We show how our point of view agrees with the spirit of conjectures of Fock-Goncharov concerning the parametrization of a basis of the upper cluster algebra by points in the tropical X-variety.

math.RT↗
arXiv2010

Cluster algebras via cluster categories with infinite-dimensional morphism spaces

We apply our previous work on cluster characters for Hom-infinite cluster categories to the theory of cluster algebras. We give a new proof of Conjectures 5.4, 6.13, 7.2, 7.10 and 7.12 of Fomin and Zelevinsky's Cluster algebras IV for skew-symmetric cluster algebras. We also construct an explicit bijection sending certain objects of the cluster category to the decorated representations of Derksen, Weyman and Zelevinsky, and show that it is compatible with mutations in both settings. Using this map, we give a categorical interpretation of the E-invariant and show that an arbitrary decorated representation with vanishing E-invariant is characterized by its g-vector. Finally, we obtain a substitution formula for cluster characters of not necessarily rigid objects.

math.RT↗
arXiv2010

Cluster characters for cluster categories with infinite-dimensional morphism spaces

We prove the existence of cluster characters for Hom-infinite cluster categories. For this purpose, we introduce a suitable mutation-invariant subcategory of the cluster category. We sketch how to apply our results in order to categorify any skew-symmetric cluster algebra. More applications and a comparison to Derksen-Weyman-Zelevinsky's results will be given in a future paper.

math.RT↗
arXiv2009

Gentle algebras arising from surface triangulations

In this paper, we associate an algebra A(T) to a triangulation T of a surface S with a set of boundary marking points. This algebra A(T) is gentle and Gorenstein of dimension one. We also prove that A(T) is cluster-tilted if and only if it is cluster-tilted of type A or A tilde, or if and only if the surface S is a disc or an annulus. Moreover all cluster-tilted algebras of type A or A tilde are obtained in this way.

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