category of measurable spaces

Notation Meas\Meas Objects measurable spaces Morphisms measurable maps Related Top\TopUnif\Unif External nLab Link

This category is similar to the category of topological spaces. For instance, limits and colimits can be constructed in the same way. However, a main difference is that this category is not infinitary distributive.

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 with the unique σ\sigma-algebra
  • initial object: empty set with the unique σ\sigma-algebra
  • products: direct products with the product σ\sigma-algebra
  • coproducts: disjoint union with the obvious σ\sigma-algebra

Special morphisms

  • isomorphisms: bijective measurable maps that map measurable sets to measurable sets
  • monomorphisms: injective measurable maps
  • epimorphisms: surjective measurable maps
  • regular monomorphisms: embeddings
  • regular epimorphisms: A measurable map f:XYf : X \to Y is a regular epimorphism iff ff is surjective and ff is a quotient map, meaning that a subset of YY is measurable when its ff-preimage is measurable.

Comments

  • The thread MSE/5024471 asks for the finitely presentable objects of this category.