Standard Young Tableaux Of Shape Research Articles

Equidistribution of set-valued statistics on standard Young tableaux and transversals

As a natural generalization of permutations, transversals of Young diagrams play an important role in the study of pattern avoiding permutations. Let Tλ(τ) and STλ(τ) denote the set of τ-avoiding transversals and τ-avoiding symmetric transversals of a Young diagram λ, respectively. In this paper, we are mainly concerned with the distribution of the peak set and the valley set on standard Young tableaux and pattern avoiding transversals. In particular, we prove that the peak set and the valley set are equidistributed on the standard Young tableaux of shape λ/μ for any skew diagram λ/μ. The equidistribution enables us to show that the peak set is equidistributed over Tλ(12⋯kτ) (resp. STλ(12⋯kτ)) and Tλ(k⋯21τ) (resp. STλ(k⋯21τ)) for any Young diagram λ and any permutation τ of {k+1,k+2,…,k+m} with k,m≥1. Our results are refinements of the result of Backelin-West-Xin which states that |Tλ(12⋯kτ)|=|Tλ(k⋯21τ)| and the result of Bousquet-Mélou and Steingrímsson which states that |STλ(12⋯kτ)|=|STλ(k⋯21τ)|. As applications, we are able to•confirm a recent conjecture posed by Yan-Wang-Zhou which asserts that the peak set is equidistributed over 12⋯kτ-avoiding involutions and k⋯21τ-avoiding involutions;•prove that alternating involutions avoiding the pattern 12⋯kτ are equinumerous with alternating involutions avoiding the pattern k⋯21τ, paralleling the result of Backelin-West-Xin for permutations, the result of Bousquet-Mélou and Steingrímsson for involutions, and the result of Yan for alternating permutations.

De Finetti Lattices and Magog Triangles

The order ideal $B_{n,2}$ of the Boolean lattice $B_n$ consists of all subsets of size at most $2$. Let $F_{n,2}$ denote the poset refinement of $B_{n,2}$ induced by the rules: $i < j$ implies $\{i \} \prec \{ j \}$ and $\{i,k \} \prec \{j,k\}$. We give an elementary bijection from the set $\mathcal{F}_{n,2}$ of linear extensions of $F_{n,2}$ to the set of shifted standard Young tableau of shape $(n, n-1, \ldots, 1)$, which are counted by the strict-sense ballot numbers. We find a more surprising result when considering the set $\mathcal{F}_{n,2}^{1}$ of minimal poset refinements in which each singleton is comparable with all of the doubletons. We show that $\mathcal{F}_{n,2}^{1}$ is in bijection with magog triangles, and therefore is equinumerous with alternating sign matrices. We adopt our proof techniques to show that row reversal of an alternating sign matrix corresponds to a natural involution on gog triangles.

Product formulas for certain skew tableaux

The hook length formula gives a product formula for the number of standard Young tableaux of a partition shape. The number of standard Young tableaux of a skew shape does not always have a product formula. However, for some special skew shapes, there is a product formula. Recently, Morales, Pak and Panova joint with Krattenthaler conjectured a product formula for the number of standard Young tableaux of shape λ∕μ for λ=((2a+c)c+a,(a+c)a) and μ=(a+1,aa−1,1). They also conjectured a product formula for the number of standard Young tableaux of a certain skew shifted shape. In this paper we prove their conjectures using Selberg-type integrals. We also give a generalization of MacMahon’s box theorem and a product formula for the trace generating function for a certain skew shape, which is a generalization of a recent result of Morales, Pak and Panova.

Two Partial Orders for Standard Young Tableaux

In this manuscript we show that two partial orders defined on the set of standard Young tableaux of shape $\alpha$ are equivalent. In fact, we give two proofs for the equivalence of the box order and the dominance order for tableaux. Both are algorithmic. The first of these proofs emphasizes links to the Bruhat order for the symmetric group and the second provides a more straightforward construction of the cover relations. This work is motivated by the known result that the equivalence of the two combinatorial orders leads to a description of the geometry of the representation space of invariant subspaces of nilpotent linear operators.

Lattice Paths, Young Tableaux, and Weight Multiplicities

For $${\ell \geq 1}$$ and $${k \geq 2}$$ , we consider certain admissible sequences of k−1 lattice paths in a colored $${\ell \times \ell}$$ square. We show that the number of such admissible sequences of lattice paths is given by the sum of squares of the number of standard Young tableaux of shape $${\lambda \vdash \ell}$$ with $${l(\lambda) \leq k}$$ , which is also the number of (k + 1)k··· 21-avoiding permutations in $${S_\ell}$$ . Finally, we apply this result to the representation theory of the affine Lie algebra $${\widehat{sl}(n)}$$ and show that this gives the multiplicity of certain maximal dominant weights in the irreducible highest weight $${\widehat{sl}(n)}$$ -module $${V(k \Lambda_0)}$$ .

Enumeration formulas for standard Young tableaux of nearly hollow rectangular shapes

This paper considers the enumeration problem of a generalization of standard Young tableau (SYT) of truncated shape. Let λ∖μ|{(i0,j0)} be the SYT of shape λ truncated by μ whose upper left cell is (i0,j0), where λ and μ are partitions of integers. The summation representation of the number of SYT of the truncated shape (n+k+2,(n+2)m+1)∖(nm)|{(2,2)} is derived. Consequently, three closed formulas for SYT of hollow shapes are obtained, including the cases of (i). m=n=1, (ii). k=0, and (iii). k=1,m=n. Finally, an open problem is posed.

Generating Functions for Inverted Semistandard Young Tableaux and Generalized Ballot Numbers

An inverted semistandard Young tableau is a row-standard tableau along with a collection of inversion pairs that quantify how far the tableau is from being column semistandard. Such a tableau with precisely $k$ inversion pairs is said to be a $k$-inverted semistandard Young tableau. Building upon earlier work by Fresse and the author, this paper develops generating functions for the numbers of $k$-inverted semistandard Young tableaux of various shapes $\lambda$ and contents $\mu$. An easily-calculable generating function is given for the number of $k$-inverted semistandard Young tableaux that "standardize" to a fixed semistandard Young tableau. For $m$-row shapes $\lambda$ and standard content $\mu$, the total number of $k$-inverted standard Young tableaux of shape $\lambda$ is then enumerated by relating such tableaux to $m$-dimensional generalizations of Dyck paths and counting the numbers of "returns to ground" in those paths. In the rectangular specialization of $\lambda = n^m$ this yields a generating function that involves $m$-dimensional analogues of the famed Ballot numbers. Our various results are then used to directly enumerate all $k$-inverted semistandard Young tableaux with arbitrary content and two-row shape $\lambda = a^1 b^1$, as well as all $k$-inverted standard Young tableaux with two-column shape $\lambda=2^n$.

Pattern Avoidance and Young Tableaux

This paper extends Lewis's bijection (J. Combin. Theorey Ser. A 118, 2011) to a bijection between a more general class $\mathcal{L}(n,k,I)$ of permutations and the set of standard Young tableaux of shape $\langle (k+1)^n\rangle$, so the cardinality\[|\mathcal{L}(n,k,I)|=f^{\langle (k+1)^n\rangle},\]is independent of the choice of $I\subseteq [n]$. As a consequence, we obtain some new combinatorial realizations and identities on Catalan numbers. In the end, we raise a problem on finding a bijection between $\mathcal{L}(n,k,I)$ and $\mathcal{L}(n,k,I')$ for distinct $I$ and $I'$.

The Selberg integral and Young books

The Selberg integral is an important integral first evaluated by Selberg in 1944. Stanley found a combinatorial interpretation of the Selberg integral in terms of permutations. In this paper, new combinatorial objects “Young books” are introduced and shown to have a connection with the Selberg integral. This connection gives an enumeration formula for Young books. It is shown that special cases of Young books become standard Young tableaux of various shapes: shifted staircases, squares, certain skew shapes, and certain truncated shapes. As a consequence, product formulas for the number of standard Young tableaux of these shapes are obtained.

Face Rings of Cycles, Associahedra, and Standard Young Tableaux

We show that $J_n$, the Stanley-Reisner ideal of the $n$-cycle, has a free resolution supported on the $(n-3)$-dimensional simplicial associahedron $A_n$. This resolution is not minimal for $n \geq 6$; in this case the Betti numbers of $J_n$ are strictly smaller than the $f$-vector of $A_n$. We show that in fact the Betti numbers $\beta_{d}$ of $J_n$ are in bijection with the number of standard Young tableaux of shape $(d+1, 2, 1^{n-d-3})$. This complements the fact that the number of $(d-1)$-dimensional faces of $A_n$ are given by the number of standard Young tableaux of (super)shape $(d+1, d+1, 1^{n-d-3})$; a bijective proof of this result was first provided by Stanley. An application of discrete Morse theory yields a cellular resolution of $J_n$ that we show is minimal at the first syzygy. We furthermore exhibit a simple involution on the set of associahedron tableaux with fixed points given by the Betti tableaux, suggesting a Morse matching and in particular a poset structure on these objects.

Asymptotics for minimal overlapping patterns for generalized Euler permutations, standard tableaux of rectangular shape, and column strict arrays

A permutation $\tau$ in the symmetric group $S_j$ is minimally overlapping if any two consecutive occurrences of $\tau$ in a permutation $\sigma$ can share at most one element. B\'ona \cite{B} showed that the proportion of minimal overlapping patterns in $S_j$ is at least $3 -e$. Given a permutation $\sigma$, we let $\text{Des}(\sigma)$ denote the set of descents of $\sigma$. We study the class of permutations $\sigma \in S_{kn}$ whose descent set is contained in the set $\{k,2k, \ldots (n-1)k\}$. For example, up-down permutations in $S_{2n}$ are the set of permutations whose descent equal $\sigma$ such that $\text{Des}(\sigma) = \{2,4, \ldots, 2n-2\}$. There are natural analogues of the minimal overlapping permutations for such classes of permutations and we study the proportion of minimal overlapping patterns for each such class. We show that the proportion of minimal overlapping permutations in such classes approaches $1$ as $k$ goes to infinity. We also study the proportion of minimal overlapping patterns in standard Young tableaux of shape $(n^k)$.

The Selberg integral and Young books

The Selberg integral is an important integral first evaluated by Selberg in 1944. Stanley found a combinatorial interpretation of the Selberg integral in terms of permutations. In this paper, new combinatorial objects "Young books'' are introduced and shown to have a connection with the Selberg integral. This connection gives an enumeration formula for Young books. It is shown that special cases of Young books become standard Young tableaux of various shapes: shifted staircases, squares, certain skew shapes, and certain truncated shapes. As a consequence, enumeration formulas for standard Young tableaux of these shapes are obtained. L’intégrale de Selberg est une partie intégrante importante abord évaluée par Selberg en 1944. Stanley a trouvé une interprétation combinatoire de la Selberg aide en permutations. Dans ce papier, de nouveaux objets combinatoires “livres de Young” sont introduits et présentés à avoir un lien avec l’intégrale de Selberg. Cette connexion donne une formule d'énumération pour les livres de Young. Il est démontré que des cas spéciaux de livres de Young deviennent tableaux standards de Young de formes diverses: escaliers décalés, places, certaines formes gauches et certaines formes tronquées. En conséquence, l’énumération des formules pour tableaux standards de Young de ces formes sont obtenues.

Wronskians, cyclic group actions, and ribbon tableaux

The Wronski map is a finite, PGL_2(C)-equivariant morphism from the Grassmannian Gr(d,n) to a projective space (the projectivization of a vector space of polynomials). We consider the following problem. If C_r < PGL_2(C) is a cyclic subgroup of order r, how may C_r-fixed points are in the in a fibre of the Wronski map over a C_r-fixed point in the base? In this paper, we compute a general answer in terms of r-ribbon tableaux. When r=2, this computation gives the number of real points in the fibre of the Wronski map over a real polynomial with purely imaginary roots. More generally, we can compute the number of real points in certain intersections of Schubert varieties. When r divides d(n-d) our main result says that the generic number of C_r-fixed points in the fibre is the number of standard r-ribbon tableaux rectangular shape (n-d)^d. Computing by a different method, we show that the answer in this case is also given by the number of of standard Young tableaux of shape (n-d)^d that are invariant under N/r iterations of jeu de taquin promotion. Together, these two results give a new proof of Rhoades' cyclic sieving theorem for promotion on rectangular tableaux. We prove analogous results for dihedral group actions.

Alternating Permutations with Restrictions and Standard Young Tableaux

In this paper, we establish bijections between the set of 4123-avoiding down-up alternating permutations of length $2n$ and the set of standard Young tableaux of shape $(n,n,n)$, and between the set of 4123-avoiding down-up alternating permutations of length $2n-1$ and the set of shifted standard Young tableaux of shape $(n+1, n, n-1)$ via an intermediate structure of Yamanouchi words. Moreover, we show that 4123-avoiding up-down alternating permutations of length $2n+1$ are in one-to-one correspondence with standard Young tableaux of shape $(n+1,n,n-1)$, and 4123-avoiding up-down alternating permutations of length $2n$ are in bijection with shifted standard Young tableaux of shape $(n+2,n,n-2)$.

Generating Trees and Pattern Avoidance in Alternating Permutations

We extend earlier work of the same author to enumerate alternating permutations avoiding the permutation pattern $2143$. We use a generating tree approach to construct a recursive bijection between the set $A_{2n}(2143)$ of alternating permutations of length $2n$ avoiding $2143$ and the set of standard Young tableaux of shape $\langle n, n, n\rangle$, and between the set $A_{2n + 1}(2143)$ of alternating permutations of length $2n + 1$ avoiding $2143$ and the set of shifted standard Young tableaux of shape $\langle n + 2, n + 1, n\rangle$. We also give a number of conjectures and open questions on pattern avoidance in alternating permutations and generalizations thereof.

A simple bijection between standard 3×n tableaux and irreducible webs for $\mathfrak{sl}_{3}$

Combinatorial spiders are a model for the invariant space of the tensor product of representations. The basic objects, webs, are certain directed planar graphs with boundary; algebraic operations on representations correspond to graph-theoretic operations on webs. Kuperberg developed spiders for rank 2 Lie algebras and $\mathfrak {sl}_{2}$ . Building on a result of Kuperberg, Khovanov–Kuperberg found a recursive algorithm giving a bijection between standard Young tableaux of shape 3×n and irreducible webs for $\mathfrak{sl}_{3}$ whose boundary vertices are all sources. In this paper, we give a simple and explicit map from standard Young tableaux of shape 3×n to irreducible webs for $\mathfrak {sl}_{3}$ whose boundary vertices are all sources and show that it is the same as Khovanov–Kuperberg’s map. Our construction generalizes to some webs with both sources and sinks on the boundary. Moreover, it allows us to extend the correspondence between webs and tableaux in two ways. First, we provide a short, geometric proof of Petersen–Pylyavskyy–Rhoades’s recent result that rotation of webs corresponds to jeu-de-taquin promotion on 3×n tableaux. Second, we define another natural operation on tableaux called a shuffle and show that it corresponds to the join of two webs. Our main tool is an intermediary object between tableaux and webs that we call an m-diagram. The construction of m-diagrams, like many of our results, applies to shapes of tableaux other than 3×n.

Pattern avoidance for alternating permutations and Young tableaux

We define a class L n , k of permutations that generalizes alternating (up–down) permutations and give bijective proofs of certain pattern-avoidance results for this class. As a special case of our results, we give bijections between the set A 2 n ( 1234 ) of alternating permutations of length 2 n with no four-term increasing subsequence and standard Young tableaux of shape 〈 3 n 〉 , and between the set A 2 n + 1 ( 1234 ) and standard Young tableaux of shape 〈 3 n − 1 , 2 , 1 〉 . This represents the first enumeration of alternating permutations avoiding a pattern of length four. We also extend previous work on doubly-alternating permutations (alternating permutations whose inverses are alternating) to our more general context. The set L n , k may be viewed as the set of reading words of the standard Young tableaux of a certain skew shape. In the last section of the paper, we expand our study to consider pattern avoidance in the reading words of standard Young tableaux of any skew shape. We show bijectively that the number of standard Young tableaux of shape λ / μ whose reading words avoid 213 is a natural μ-analogue of the Catalan numbers (and in particular does not depend on λ, up to a simple technical condition), and that there are similar results for the patterns 132, 231 and 312.

Q-Analog of tableau containment

We prove a q-analog of the following result due to McKay, Morse and Wilf: the probability that a random standard Young tableau of size n contains a fixed standard Young tableau of shape λ ⊢ k tends to f λ / k ! in the large n limit, where f λ is the number of standard Young tableaux of shape λ. We also consider the probability that a random pair ( P , Q ) of standard Young tableaux of the same shape contains a fixed pair ( A , B ) of standard Young tableaux.

An asymptotic version of a theorem of Knuth

A well-known theorem of Knuth establishes a bijection between permutations in S ( N ) with no decreasing subsequence of length three and rectangular standard Young tableaux of shape R ( 2 , N ) . We prove an asymptotic version of this result: for any fixed integer d ⩾ 2 , the number of permutations in S ( d n ) with no decreasing subsequence of length d + 1 is asymptotically equal, as n → ∞ , to the number of standard Young tableaux on the rectangle R ( d , 2 n ) . This yields a new proof of Regevʼs theorem on the asymptotic number of permutations without long decreasing subsequences, and consequently an alternative, elementary evaluation of Mehtaʼs integral at β = 2 .

Pattern avoidance in alternating permutations and tableaux (extended abstract)

We give bijective proofs of pattern-avoidance results for a class of permutations generalizing alternating permutations. The bijections employed include a modified form of the RSK insertion algorithm and recursive bijections based on generating trees. As special cases, we show that the sets $A_{2n}(1234)$ and $A_{2n}(2143)$ are in bijection with standard Young tableaux of shape $\langle 3^n \rangle$. Alternating permutations may be viewed as the reading words of standard Young tableaux of a certain skew shape. In the last section of the paper, we study pattern avoidance in the reading words of standard Young tableaux of any skew shape. We show bijectively that the number of standard Young tableaux of shape $\lambda / \mu$ whose reading words avoid $213$ is a natural $\mu$-analogue of the Catalan numbers. Similar results for the patterns $132$, $231$ and $312$. Nous présentons des preuves bijectives de résultats pour une classe de permutations à motifs exclus qui généralisent les permutations alternantes. Les bijections utilisées reposent sur une modification de l'algorithme d'insertion "RSK" et des bijections récursives basées sur des arbres de génération. Comme cas particuliers, nous montrons que les ensembles $A_{2n}(1234)$ et $A_{2n}(2143)$ sont en bijection avec les tableaux standards de Young de la forme $\langle 3^n \rangle$. Une permutation alternante peut être considérée comme le mot de lecture de certain skew tableau. Dans la dernière section de l'article, nous étudions l'évitement des motifs dans les mots de lecture de skew tableaux généraux. Nous montrons bijectivement que le nombre de tableaux standards de forme $\lambda / \mu$ dont les mots de lecture évitent $213$ est un $\mu$-analogue naturel des nombres de Catalan. Des résultats analogues sont valables pour les motifs $132$, $231$ et $312$.