2018-02-07: Fredrik Nordvall Forsberg (MSP)

Sat, 21 Oct 2023 21:24:08 +0100

Fredrik Nordvall Forsberg (MSP)

MSP 101: The adjoint functor theorem

Abstract

Adjoint functors arise everywhere, but how do we find them? It is a fun exercise to prove that right adjoints preserve limits, and, dually, that left adjoints preserve colimits. An adjoint functor theorem is a statement that (under certain conditions) the converse holds: a functor which preserves limits is a right adjoint. I will discuss the General Adjoint Functor Theorem, and why Peter Johnstone considers it fundamentally useless.

2018-02-07 15:00:00 UTC
LT1310