Enriched category

From Cattheory
Revision as of 15:08, 29 December 2009 by Vipul (talk | contribs) (→‎Definition)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Definition

Suppose M is a monoidal category. A category enriched in M is defined as a C equipped with the following data:

  • A collection of objects ObC.
  • For any objects A,B∈ObC, an object C(A,B)∈ObM.
  • For any object A∈ObC, a unit map uA from the unit object in M to C(A,A).
  • For any objects A,B,C∈ObC, a morphism in M:

∘:C(B,C)⊗C(A,B)→C(A,C)

where ⊗ denotes the monoidal operation on M.

satisfying the following conditions:

  • For any A,B,C,D∈ObC, with f∈C(A,B),g∈C(B,C),h∈C(C,D), we have h∘(g∘f)=(h∘g)∘f.
  • For any A,B∈ObC, the map ∘:C(B,B)⊗C(A,B)→C(A,B), composed with uB on the first coordinate, gives the identity map on the second coordinate. Similarly, the other way around. Need to make more precise -- Fill this in later