Metamath Proof Explorer
Description: A function measurable w.r.t. to a sigma-algebra, is actually a function.
(Contributed by Glauco Siliprandi, 26-Jun-2021)
|
|
Ref |
Expression |
|
Hypotheses |
smff.s |
⊢ ( 𝜑 → 𝑆 ∈ SAlg ) |
|
|
smff.f |
⊢ ( 𝜑 → 𝐹 ∈ ( SMblFn ‘ 𝑆 ) ) |
|
|
smff.d |
⊢ 𝐷 = dom 𝐹 |
|
Assertion |
smff |
⊢ ( 𝜑 → 𝐹 : 𝐷 ⟶ ℝ ) |
Proof
Step |
Hyp |
Ref |
Expression |
1 |
|
smff.s |
⊢ ( 𝜑 → 𝑆 ∈ SAlg ) |
2 |
|
smff.f |
⊢ ( 𝜑 → 𝐹 ∈ ( SMblFn ‘ 𝑆 ) ) |
3 |
|
smff.d |
⊢ 𝐷 = dom 𝐹 |
4 |
1 3
|
issmf |
⊢ ( 𝜑 → ( 𝐹 ∈ ( SMblFn ‘ 𝑆 ) ↔ ( 𝐷 ⊆ ∪ 𝑆 ∧ 𝐹 : 𝐷 ⟶ ℝ ∧ ∀ 𝑎 ∈ ℝ { 𝑥 ∈ 𝐷 ∣ ( 𝐹 ‘ 𝑥 ) < 𝑎 } ∈ ( 𝑆 ↾t 𝐷 ) ) ) ) |
5 |
2 4
|
mpbid |
⊢ ( 𝜑 → ( 𝐷 ⊆ ∪ 𝑆 ∧ 𝐹 : 𝐷 ⟶ ℝ ∧ ∀ 𝑎 ∈ ℝ { 𝑥 ∈ 𝐷 ∣ ( 𝐹 ‘ 𝑥 ) < 𝑎 } ∈ ( 𝑆 ↾t 𝐷 ) ) ) |
6 |
5
|
simp2d |
⊢ ( 𝜑 → 𝐹 : 𝐷 ⟶ ℝ ) |