Monday, 28 April 2014

ct.category theory - Probably easy: Why is f*:A^C'->A^C continuous and cocontinuous for any functor f:C->C'?

Let $f:Cto C'$ be a functor, and let $A$ be a locally presentable, complete, and cocomplete category. Then according to the paper I'm reading, the pullback functor, $f^*:A^{C'}to A^C$ (given by precomposition with $f$), admits left and right adjoints $f_!$ and $f_*$. It's clear that the proof of this fact follows from the adjoint functor theorem, so it suffices to show that $f^*$ is continuous and cocontinuous.



However, it's not clear to me how to show this fact.



Question:



Using the notation above, why is $f^*$ continuous and cocontinuous?



Sorry if this ends up being too easy.

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