Categories 7 Yoneda's lemma

This lecture is part of an online course on categories. Any object of a category can be thought of as a representable functor in the category of presheaves. We give several examples of representable functors. Then we state Yoneda's lemma, which roughly that morphisms of objects are he same as morphisms of the corresponding presheaves. For the other lectures in the course see    • Categories for the idle mathematician