Past exam of the mathematics course of the University of Cambridge 2008 iii Paper 4 3 b Solution Created 2026-10-03 Updated 2026-10-14
For generators of , write , . ThenFor each , define a two-dimensional module on basis by , , , . Every product of two of these operators is zero, so the defining relations hold even when .
The action of is one nonzero nilpotent Jordan block. A decomposition of would decompose its restriction to , which is already indecomposable. Thus is indecomposable. An isomorphism commutes with and , and consequentlySince is invertible and , . The infinite field supplies infinitely many parameters, proving has infinite representation type. This is the parameter family for an elementary abelian p-group.