Post Closed as "too localized" by Qiaochu Yuan, David Roberts, Daniel Moskovich, Zev Chonoles, Pete L. Clark

# Interesting examples of adjoint functors?

It would be useful to a beginner of category theory to see some examples of adjoint pairs which are not equivalences, and which are not forgetful/inclusion types. Of course, a first is the standard Hom-tensor duality.