Metamath Proof Explorer


Theorem orvccel

Description: If the relation produces closed sets, preimage maps by a measurable function are measurable sets. (Contributed by Thierry Arnoux, 21-Jan-2017)

Ref Expression
Hypotheses orvccel.1 ⊢ φ → S ∈ ⋃ ran ⁡ sigAlgebra
orvccel.2 ⊢ φ → J ∈ Top
orvccel.3 ⊢ φ → X ∈ S MblFn μ 𝛔 ⁡ J
orvccel.4 ⊢ φ → A ∈ V
orvccel.5 ⊢ φ → y ∈ ⋃ J | y R A ∈ Clsd ⁡ J
Assertion orvccel ⊢ φ → X R RV/c A ∈ S

Proof

Step Hyp Ref Expression
1 orvccel.1 ⊢ φ → S ∈ ⋃ ran ⁡ sigAlgebra
2 orvccel.2 ⊢ φ → J ∈ Top
3 orvccel.3 ⊢ φ → X ∈ S MblFn μ 𝛔 ⁡ J
4 orvccel.4 ⊢ φ → A ∈ V
5 orvccel.5 ⊢ φ → y ∈ ⋃ J | y R A ∈ Clsd ⁡ J
6 1 2 3 4 orvcval4 ⊢ φ → X R RV/c A = X -1 y ∈ ⋃ J | y R A
7 2 sgsiga ⊢ φ → 𝛔 ⁡ J ∈ ⋃ ran ⁡ sigAlgebra
8 cldssbrsiga ⊢ J ∈ Top → Clsd ⁡ J ⊆ 𝛔 ⁡ J
9 2 8 syl ⊢ φ → Clsd ⁡ J ⊆ 𝛔 ⁡ J
10 9 5 sseldd ⊢ φ → y ∈ ⋃ J | y R A ∈ 𝛔 ⁡ J
11 1 7 3 10 mbfmcnvima ⊢ φ → X -1 y ∈ ⋃ J | y R A ∈ S
12 6 11 eqeltrd ⊢ φ → X R RV/c A ∈ S