The main result of this page is that

Theorem

Every Frobenius algebra has a unique coalgebra structure for which the Frobenius form is the counit which is -linear.
Conversely, given any coalgebra,

The Category of Frobenius Algebras

Frobenius Homomorphism

A Frobenius homomorphism between two Frobenius algebras is an algebra homomorphism that is also a coalgebra homomorphism.