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 φSransigAlgebra
orvccel.2 φJTop
orvccel.3 φXSMblFnμ𝛔J
orvccel.4 φAV
orvccel.5 φyJ|yRAClsdJ
Assertion orvccel φXRRV/cAS

Proof

Step Hyp Ref Expression
1 orvccel.1 φSransigAlgebra
2 orvccel.2 φJTop
3 orvccel.3 φXSMblFnμ𝛔J
4 orvccel.4 φAV
5 orvccel.5 φyJ|yRAClsdJ
6 1 2 3 4 orvcval4 φXRRV/cA=X-1yJ|yRA
7 2 sgsiga φ𝛔JransigAlgebra
8 cldssbrsiga JTopClsdJ𝛔J
9 2 8 syl φClsdJ𝛔J
10 9 5 sseldd φyJ|yRA𝛔J
11 1 7 3 10 mbfmcnvima φX-1yJ|yRAS
12 6 11 eqeltrd φXRRV/cAS