Metamath Proof Explorer


Theorem smfpimioompt

Description: Given a function measurable w.r.t. to a sigma-algebra, the preimage of an open interval is in the subspace sigma-algebra induced by its domain. (Contributed by Glauco Siliprandi, 26-Jun-2021)

Ref Expression
Hypotheses smfpimioompt.x x φ
smfpimioompt.s φ S SAlg
smfpimioompt.a φ A V
smfpimioompt.b φ x A B W
smfpimioompt.m φ x A B SMblFn S
smfpimioompt.l φ L *
smfpimioompt.r φ R *
Assertion smfpimioompt φ x A | B L R S 𝑡 A

Proof

Step Hyp Ref Expression
1 smfpimioompt.x x φ
2 smfpimioompt.s φ S SAlg
3 smfpimioompt.a φ A V
4 smfpimioompt.b φ x A B W
5 smfpimioompt.m φ x A B SMblFn S
6 smfpimioompt.l φ L *
7 smfpimioompt.r φ R *
8 eqid dom x A B = dom x A B
9 2 5 8 smff φ x A B : dom x A B
10 eqid x A B = x A B
11 1 10 4 dmmptdf φ dom x A B = A
12 11 feq2d φ x A B : dom x A B x A B : A
13 9 12 mpbid φ x A B : A
14 13 fvmptelrn φ x A B
15 14 rexrd φ x A B *
16 1 6 7 15 pimiooltgt φ x A | B L R = x A | B < R x A | L < B
17 eqid S 𝑡 A = S 𝑡 A
18 2 3 17 subsalsal φ S 𝑡 A SAlg
19 1 2 4 5 7 smfpimltxrmpt φ x A | B < R S 𝑡 A
20 1 2 4 5 6 smfpimgtxrmpt φ x A | L < B S 𝑡 A
21 18 19 20 salincld φ x A | B < R x A | L < B S 𝑡 A
22 16 21 eqeltrd φ x A | B L R S 𝑡 A