Proof of the 2-part compositional shuffle conjecture

Author(s):  
Adriano M. Garsia ◽  
Gouce Xin ◽  
Mike Zabrocki
Keyword(s):  
2012 ◽  
Vol 64 (4) ◽  
pp. 822-844 ◽  
Author(s):  
J. Haglund ◽  
J. Morse ◽  
M. Zabrocki

Abstract We introduce a q, t-enumeration of Dyck paths that are forced to touch the main diagonal at specific points and forbidden to touch elsewhere and conjecture that it describes the action of the Macdonald theory ∇ operator applied to a Hall–Littlewood polynomial. Our conjecture refines several earlier conjectures concerning the space of diagonal harmonics including the “shuffle conjecture” (Duke J. Math. 126 (2005), pp. 195 − 232) for ∇ en[X]. We bring to light that certain generalized Hall–Littlewood polynomials indexed by compositions are the building blocks for the algebraic combinatorial theory of q, t-Catalan sequences, and we prove a number of identities involving these functions.


2017 ◽  
Vol 31 (3) ◽  
pp. 661-697 ◽  
Author(s):  
Erik Carlsson ◽  
Anton Mellit
Keyword(s):  

2019 ◽  
Vol 57 (1) ◽  
pp. 77-89 ◽  
Author(s):  
Stephanie van Willigenburg
Keyword(s):  

2017 ◽  
Vol 145 ◽  
pp. 57-100 ◽  
Author(s):  
Adriano Garsia ◽  
Emily Sergel Leven ◽  
Nolan Wallach ◽  
Guoce Xin

2012 ◽  
Vol DMTCS Proceedings vol. AR,... (Proceedings) ◽  
Author(s):  
Angela Hicks

International audience In a 2010 paper Haglund, Morse, and Zabrocki studied the family of polynomials $\nabla C_{p1}\dots C_{pk}1$ , where $p=(p_1,\ldots,p_k)$ is a composition, $\nabla$ is the Bergeron-Garsia Macdonald operator and the $C_\alpha$ are certain slightly modified Hall-Littlewood vertex operators. They conjecture that these polynomials enumerate a composition indexed family of parking functions by area, dinv and an appropriate quasi-symmetric function. This refinement of the nearly decade old ``Shuffle Conjecture,'' when combined with properties of the Hall-Littlewood operators can be shown to imply the existence of certain bijections between these families of parking functions. In previous work to appear in her PhD thesis, the author has shown that the existence of these bijections follows from some relatively simple properties of a certain family of polynomials in one variable x with coefficients in $\mathbb{N}[q]$. In this paper we introduce those polynomials, explain their connection to the conjecture of Haglund, Morse, and Zabrocki, and explore some of their surprising properties, both proven and conjectured. Dans un article de 2010, Haglund, Morse et Zabrocki étudient la famille de polynômes $\nabla C_{p1}\dots C_{pk}1$ où $p=(p_1,\ldots,p_k)$ est une composition, $\nabla$ est l’opérateur de Bergeron-Garsia et les $C_\alpha$ sont des opérateurs ``vertex'' de Hall-Littlewood légèrement altérés. Il posent la conjecture que ces polynômes donnent l’énumération d'une famille de fonctions ``parking'', indexées par des compositions, par aire, le ``dinv'' et une fonction quasi-symétrique associée. Cette conjecture raffine la conjecture ``Shuffle'', qui est âgée de presque dix ans. On peut montrer, a partir de cette conjecture, que les propriétés des opérateurs de Hall-Littlewood, impliquent l'existence de certaines bijections entre ces familles de fonctions ``parking''. Dans un précédent travail , qui fait partie de sa thèse de doctorat, l'auteur montre que l’existence de ces bijections découle de certaines propriétés relativement simples d'une famille de polynômes à une variable x, avec coefficients dans $\mathbb{N}[q]$. Dans cet article, on introduit ces polynômes, on explique leur connexion avec la conjecture de Haglund, Morse et Zabrocki, et on explore certaines de leurs propriétés surprenantes, qu'elles soient prouvées ou seulement conjecturées.


2013 ◽  
Vol DMTCS Proceedings vol. AS,... (Proceedings) ◽  
Author(s):  
Yeonkyung Kim

International audience In this article, we show how the compositional refinement of the ``Shuffle Conjecture'' due to Jim Haglund, Jennifer Morse, and Mike Zabrocki can be used to express the image of a Schur function under the Bergeron-Garsia Nabla operator as a weighted sum of a suitable collection of ``Parking Functions.'' The validity of these expressions is, of course, going to be conjectural until the compositional refinement of the Shuffle Conjecture is established.


2014 ◽  
Vol 5 (1) ◽  
pp. 31-50
Author(s):  
Angela Hicks ◽  
Emily Leven
Keyword(s):  

2014 ◽  
Vol DMTCS Proceedings vol. AT,... (Proceedings) ◽  
Author(s):  
Emily Leven

International audience The Classical Shuffle Conjecture of Haglund et al. (2005) has a symmetric function side and a combinatorial side. The combinatorial side $q,t$-enumerates parking functions in the $n ×n$ lattice. The symmetric function side may be simply expressed as $∇ e_n$ , where $∇$ is the Macdonald eigen-operator introduced by Bergeron and Garsia (1999) and $e_n$ is the elementary symmetric function. The combinatorial side has been extended to parking functions in the $m ×n$ lattice for coprime $m,n$ by Hikita (2012). Recently, Gorsky and Negut have been able to extend the Shuffle Conjecture by combining their work (2012a, 2012b, 2013) (related to work of Schiffmann and Vasserot (2011, 2013)) with Hikita's combinatorial results. We prove this new conjecture for the cases $m=2$ and $n=2$ .


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