Past exam of the mathematics course of the University of Cambridge 2008 iii Paper 8 5 i Solution Created 2026-10-03 Updated 2026-10-14
Take , the function Hopf algebra of a finite group. Multiplication is pointwise, andThe group associativity, identity and inverse laws respectively verify coassociativity, the counit and the antipode; pointwise products show that are algebra homomorphisms. Thus is a commutative Hopf algebra.
For and , using right-to-left permutation composition, whereas . The delta function has but . Therefore .