Some new decomposable Specht modules

Abstract

We present (with proof) a new family of decomposable Specht modules for the symmetric group in characteristic 2. These Specht modules are labelled by partitions of the form $(a,3,1^b)$, and are the first new examples found for thirty years. Our method of proof is to exhibit summands isomorphic to irreducible Specht modules, by constructing explicit homomorphisms between Specht modules.

Incorrect proof of Proposition 5.2 replaced

References in corpus (1)

• An algorithm for semistandardising homomorphisms

Cited by in corpus (6)

• An algorithm for semistandardising homomorphisms
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• Decomposable Specht modules indexed by bihooks II
• The irreducible representations of the alternating group which remain irreducible in characteristic p