Reference · Finite types, distributions and Markov chains
rainbow.math.finite.set-fiber-decomposition
A finite source is the union of its fibers over its finite image.
set/source-subset-image-fiber-union
set/source-subset-image-fiber-union.{u, v} :
(A : Type u) (B : Type v) (mapping : A → B) (source : set/Set A)
→ set/subset A source (union)
where union := set/restricted-indexed-union A B (set/image A B mapping source) (fun target => set/fiber-within A B mapping source target)set/image-fiber-union-subset-source
set/image-fiber-union-subset-source.{u, v} :
(A : Type u) (B : Type v) (mapping : A → B) (source : set/Set A)
→ set/subset A (union) source
where union := set/restricted-indexed-union A B (set/image A B mapping source) (fun target => set/fiber-within A B mapping source target)set/image-fiber-union-decomposition
set/image-fiber-union-decomposition.{u, v} :
(A : Type u) (B : Type v) (mapping : A → B) (source : set/Set A)
→ proposition/conjunction (subset) (subset₁)
where subset := set/subset A source (set/restricted-indexed-union A B (set/image A B mapping source) (fun target => set/fiber-within A B mapping source target))
where subset₁ := set/subset A (set/restricted-indexed-union A B (set/image A B mapping source) (fun target => set/fiber-within A B mapping source target)) sourceset/finite-image-fiber-union
set/finite-image-fiber-union.{u, v} :
(A : Type u) (B : Type v) (mapping : A → B) (source : set/Set A)
(source-finite : set/finite A source)
→ set/finite A (union)
where union := set/restricted-indexed-union A B (set/image A B mapping source) (fun target => set/fiber-within A B mapping source target)