A Nekrasov-Okounkov type formula for affine $\widetilde{C}$

International audience In 2008, Han rediscovered an expansion of powers of Dedekind $\eta$ function due to Nekrasov and Okounkov by using Macdonald's identity in type $\widetilde{A}$. In this paper, we obtain new combinatorial expansions of powers of $\eta$, in terms of partition hook lengths, by using Macdonald's identity in type $\widetilde{C}$ and a new bijection. As applications, we derive a symplectic hook formula and a relation between Macdonald's identities in types $\widetilde{C}$, $\widetilde{B}$, and $\widetilde{BC}$. En 2008, Han a redécouvert un développement des puissances de la fonction $\eta$ de Dedekind, dû à Nekrasov et Okounkov, en utilisant l’identité de Macdonald en type $\widetilde{A}$. Dans cet article, nous obtenons un nouveau développement combinatoire des puissances de $\eta$, en termes de longueurs d’équerres de partitions, en utilisant l’identité de Macdonald en type $\widetilde{C}$ ainsi qu’une nouvelle bijection. Plusieurs applications en sont déduites, comme un analogue symplectique de la formule des équerres, ou une relation entre les identités de Macdonald en types $\widetilde{C}$, $\widetilde{B}$, et $\widetilde{BC}$.

An algorithm which generates linear extensions for a generalized Young diagram with uniform probability

International audience The purpose of this paper is to present an algorithm which generates linear extensions for a generalized Young diagram, in the sense of D. Peterson and R. A. Proctor, with uniform probability. This gives a proof of a D. Peterson's hook formula for the number of reduced decompositions of a given minuscule elements. \par Le but de ce papier est présenter un algorithme qui produit des extensions linéaires pour un Young diagramme généralisé dans le sens de D. Peterson et R. A. Proctor, avec probabilité constante. Cela donne une preuve de la hook formule d'un D. Peterson pour le nombre de décompositions réduites d'un éléments minuscules donné.

$q$-Hook formula of Gansner type for a generalized Young diagram

International audience The purpose of this paper is to present the $q$-hook formula of Gansner type for a generalized Young diagram in the sense of D. Peterson and R. A. Proctor. This gives a far-reaching generalization of a hook length formula due to J. S. Frame, G. de B. Robinson, and R. M. Thrall. Furthurmore, we give a generalization of P. MacMahon's identity as an application of the $q$-hook formula. Le but de ce papier est présenter la $q$-hook formule de type Gansner pour un Young diagramme généralisé dans le sens de D. Peterson et R. A. Proctor. Cela donne une généralisation de grande envergure d'une hook length formule dû à J. S. Frame, G. de B. Robinson, et R. M. Thrall. Furthurmore, nous donnons une généralisation de l'identité de P. MacMahon comme une application de la $q$-hook formule.

An Elementary Proof of the Hook Formula

The hook-length formula is a well known result expressing the number of standard tableaux of shape $\lambda$ in terms of the lengths of the hooks in the diagram of $\lambda$. Many proofs of this fact have been given, of varying complexity. We present here an elementary new proof which uses nothing more than the fundamental theorem of algebra. This proof was suggested by a $q,t$-analog of the hook formula given by Garsia and Tesler, and is roughly based on the inductive approach of Greene, Nijenhuis and Wilf. We also prove the hook formula in the case of shifted Young tableaux using the same technique.

Asymptotics of Young Diagrams and Hook Numbers

Asymptotic calculations are applied to study the degrees of certain sequences of characters of symmetric groups. Starting with a given partition $\mu$, we deduce several skew diagrams which are related to $\mu$. To each such skew diagram there corresponds the product of its hook numbers. By asymptotic methods we obtain some unexpected arithmetic properties between these products. The authors do not know "finite", nonasymptotic proofs of these results. The problem appeared in the study of the hook formula for various kinds of Young diagrams. The proofs are based on properties of shifted Schur functions, due to Okounkov and Olshanski. The theory of these functions arose from the asymptotic theory of Vershik and Kerov of the representations of the symmetric groups.