CatDat

category of non-empty sets

  • notation: Set\Setne
  • objects: non-empty sets
  • morphisms: maps
  • Related categories: Set\Set
  • nLab Link

This entry demonstrates that removing an object (the empty set) can drastically change the properties of a category. In particular, this category is neither complete nor cocomplete.

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 set
  • products: direct products

Special morphisms

  • isomorphisms: bijective maps
  • monomorphisms: injective maps
  • epimorphisms: surjective maps
  • regular monomorphisms: same as monomorphisms
  • regular epimorphisms: same as epimorphisms