Explicit Pieri Inclusions

By the Pieri rule, the tensor product of an exterior power and a finite-dimensional irreducible representation of a general linear group has a multiplicity-free decomposition. The embeddings of the constituents are called Pieri inclusions and were first studied by Weyman in his thesis and described explicitly by Olver. More recently, these maps have appeared in the work of Eisenbud, Fløystad, and Weyman and of Sam and Weyman to compute pure free resolutions for classical groups. In this paper, we give a new closed form, non-recursive description of Pieri inclusions. For partitions with a bounded number of distinct parts, the resulting algorithm has polynomial time complexity whereas the previously known algorithm has exponential time complexity.

Polynomial ring representations of endomorphisms of exterior powers

An explicit description of the ring of the rational polynomials in r indeterminates as a representation of the Lie algebra of the endomorphisms of the k-th exterior power of a countably infinite-dimensional vector space is given. Our description is based on results by Laksov and Throup concerning the symmetric structure of the exterior power of a polynomial ring. Our results are based on approximate versions of the vertex operators occurring in the celebrated bosonic vertex representation, due to Date, Jimbo, Kashiwara and Miwa, of the Lie algebra of all matrices of infinite size, whose entries are all zero but finitely many.

Additive Maps of Rank k Bivectors

Let ${\cal U}$ and ${\cal V}$ be linear spaces over fields $\mathbb{F}$ and $\mathbb{K}$, respectively, such that Dim$\,{\cal U}=n\geqslant 2$ and $\left|\mathbb{F}\right|\geqslant 3$. Let $\bigwedge^2{\cal U}$ be the second exterior power of ${\cal U}$. Fixing an even integer $k$ satisfying $\frac{n-1}{2}\leqslant k\leqslant n$, it is shown that a map $\psi:\bigwedge^2{\cal U}\rightarrow\bigwedge^2{\cal V}$ satisfies $\psi(u+v)=\psi(u)+\psi(v)$ for all rank $k$ bivectors $u,v\in\bigwedge^2{\cal U}$ if and only if $\psi$ is an additive map. Examples showing the indispensability of the assumption on $k$ are given.

Exterior powers of the standard E6-module: An elementary approach

For the standard [Formula: see text]-dimensional representation [Formula: see text] of the exceptional group [Formula: see text] of type [Formula: see text] we prove that [Formula: see text] is a Donkin pair if and only if the characteristic of a ground field is greater than [Formula: see text]. We also develop an elementary approach to describe submodule structure of any exterior power of [Formula: see text].

On Higher Special Elements of p-adic Representations

As a natural generalisation of the notion of “higher rank Euler system”, we develop a theory of “higher special elements” in the exterior power biduals of the Galois cohomology of $p$-adic representations. We show, in particular, that such elements encode detailed information about the structure of Galois cohomology groups and are related by families of congruences involving natural height pairings on cohomology. As a first concrete application of the approach, we use it to refine, and extend, a variety of existing results and conjectures concerning the values of derivatives of Dirichlet $L$-series.

Non-Degeneracy of 2-Forms and Pfaffian

In this article, we study the non-degeneracy of 2-forms (skew symmetric ( 0 , 2 ) -tensor) α along the Pfaffian of α . We consider a symplectic vector space V with a non-degenerate skew symmetric ( 0 , 2 ) -tensor ω , and derive various properties of the Pfaffian of α . As an application we show the non-degenerate skew symmetric ( 0 , 2 ) -tensor ω has a property of rigidity that it is determined by its exterior power.

FUJITA DECOMPOSITION AND HODGE LOCI

This paper contains two results on Hodge loci in $\mathsf{M}_{g}$. The first concerns fibrations over curves with a non-trivial flat part in the Fujita decomposition. If local Torelli theorem holds for the fibers and the fibration is non-trivial, an appropriate exterior power of the cohomology of the fiber admits a Hodge substructure. In the case of curves it follows that the moduli image of the fiber is contained in a proper Hodge locus. The second result deals with divisors in $\mathsf{M}_{g}$. It is proved that the image under the period map of a divisor in $\mathsf{M}_{g}$ is not contained in a proper totally geodesic subvariety of $\mathsf{A}_{g}$. It follows that a Hodge locus in $\mathsf{M}_{g}$ has codimension at least 2.