Category theory MOC

Category-vector space analogy

The is a striking, albeit informal, correspondence between the basic concepts of category theory and linear algebra. The following table, based on 2011. Introduction to representation theory, ยง7.6, is a summary.

Category theoryLinear algebra
category vector space
hom-set nondegenerate bilinear form
opposite categoryopposite inner product
ground field
full subcategorynondegenerate subspace
functor linear map
presheaflinear form
Yoneda lemmanondegeneracy
representable functorrepresentable form
adjoint functoradjoint operator


#state/tidy | #lang/en | #SemBr