On extensions and branching rules for modules close to completely splittable

The Ext-quiver for completely splittable representations of the symmetric group

Kleshchev has recently [7] classi®ed those modules for the symmetric group which have semisimple restriction to any Young subgroup. We determine Ext K Sd …D ;D m† where D l and D m are K Sd -modules of this type, called completely splittable. As a corollary of this and recent work of Kleshchev and Nakano, we can determine ExtGL n…K†……L…l†;L…m†† for certain simple GLn…K†-modules L…l† and L…m†. 1...

On some extensions of p-restricted completely splittable GL(n)-modules

In this paper, we calculate the space ExtGL(n)(Ln(λ), Ln(μ)), where GL(n) is the general linear group of degree n over an algebraically closed field of positive characteristic, Ln(λ) and Ln(μ) are rational irreducible GL(n)-modules with highest weights λ and μ respectively, the restriction of Ln(λ) to any Levi subgroup of GL(n) is semisimple, λ is a p-restricted weight and μ does not strictly d...

Extensions of Baer and quasi-Baer modules

Inert Module Extensions, Multiplicatively Closed Subsets Conserving Cyclic Submodules and Factorization in Modules

Introduction Suppose that  is a commutative ring with identity,  is a unitary -module and  is a multiplicatively closed subset of .  Factorization theory in commutative rings, which has a long history, still gets the attention of many researchers. Although at first, the focus of this theory was factorization properties of elements in integral domains, in the late nineties the theory was gener...

Multi-commodity Multimodal Splittable Logistics Hub Location Problem with Stochastic Demands

This study presents a multimodal hub location problem which has the capability to split commodities by limited-capacity hubs and transportation systems, based on the assumption that demands are stochastic for multi-commodity network flows. In the real world cases, demands are random over the planning horizon and those which are partially fulfilled, are lost. Thus, the present study handles dema...