12 papers
On the Humphreys-Verma Conjecture for semisimple algebraic groups of rank
Stephen Donkin, Haralampos Geranios
Let be a connected, semisimple, simply connected algebraic group over an algebraically closed field of positive characteristic. For each restricted dominant weight , there i…
On the Endomorphism Algebra of Specht Modules in Even Characteristic
Haralampos Geranios, Adam Higgins
Over fields of characteristic , Specht modules may decompose and there is no upper bound for the dimension of their endomorphism algebra. A classification of the (in)decomposabl…
On self-extensions of irreducible modules over symmetric groups
Haralampos Geranios, Alexander Kleshchev, Lucia Morotti
A conjecture going back to the eighties claims that there are no non-trivial self-extensions of irreducible modules over symmetric groups if the characteristic of the ground field…
Decompositions of some Specht modules I
Stephen Donkin, Haralampos Geranios
We give a decomposition as a direct sum of indecomposable modules of several types of Specht modules in characteristic . These include the Specht modules labelled by hooks, whos…
First Degree Cohomology of Specht Modules and Extensions of Symmetric Powers
Stephen Donkin, Haralampos Geranios
Let denote the symmetric group of degree and let be a field of positive characteristic . For we give an explicit description of the first cohomology group $H…
Injective Schur Modules
Stephen Donkin, Haralampos Geranios
We determine the partitions for which the corresponding induced module (or Schur module in the language of Buchsbaum et. al., [1]) is injective in the category of p…