CatDat

category of prosets

  • notation: Prost\mathbf{Prost}
  • objects: preordered sets (aka prosets), i.e. sets equipped with a reflexive, transitive relation
  • morphisms: order-preserving functions
  • Related categories: Pos\mathbf{Pos}
  • nLab Link

Even though there are many similarities with Pos\mathbf{Pos}, the main difference is that the forgetful functor ProstSet\mathbf{Prost} \to \mathbf{Set} has a right adjoint, mapping XX to (X,X×X)(X , X \times X) (chaotic preorder).

Satisfied Properties

Properties from the database

Deduced properties

Unsatisfied Properties

Properties from the database

Deduced properties*

*This also uses the deduced satisfied properties.

Unknown properties

Special objects

  • terminal object: singleton proset
  • initial object: empty proset
  • products: direct products with the evident preorder
  • coproducts: disjoint union with the obvious preorder that leaves the distinct summands incomparable

Special morphisms

  • isomorphisms: bijective functions that are order-preserving and order-reflecting
  • monomorphisms: injective order-preserving functions
  • epimorphisms: surjective order-preserving functions
  • regular monomorphisms: embeddings
  • regular epimorphisms: