category of partially ordered sets

Notation Pos\Pos Objects partially ordered sets (aka posets), i.e. sets equipped with a reflexive, transitive, and antisymmetric relation Morphisms order-preserving functions Related FinOrd\FinOrdPreOrd\PreOrdMono\MonoPosnoiso\Pos_{\noiso}Bin\Bin External nLab Link

Despite the many similarities with PreOrd\PreOrd, the main difference is that the forgetful functor PosSet\Pos \to \Set has no right adjoint. It is a full subcategory of Bin\Bin.

Satisfied Properties

Assigned properties

Deduced properties

Unsatisfied Properties

Assigned properties

Deduced properties*

*This also uses the deduced satisfied properties.

Unknown properties

Special objects

  • terminal object: singleton poset
  • initial object: empty poset
  • products: direct products with the evident partial order
  • coproducts: disjoint union with the obvious partial order in which distinct summands are 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: