Beck comonadicity theorem (source code)

= Beck comonadicity theorem
{c}
{wiki=Beck's_monadicity_theorem}

The Beck comonadicity theorem, dual to the <Beck monadicity theorem>, says that a left adjoint is comonadic when it reflects isomorphisms and preserves the required equalizers of pairs whose images admit split equalizers. A stronger convenient hypothesis is that it preserves all equalizers.