Metamath Proof Explorer

Theorem isrnmeas

Description: The property of being a measure on an undefined base sigma-algebra. (Contributed by Thierry Arnoux, 25-Dec-2016)

Ref Expression
Assertion isrnmeas ( 𝑀 ∈ ∪ ran measures → ( dom 𝑀 ∈ ∪ ran sigAlgebra ∧ ( 𝑀 : dom 𝑀 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 dom 𝑀 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) ) )

Proof

Step Hyp Ref Expression
1 df-meas ⊢ measures = ( 𝑠 ∈ ∪ ran sigAlgebra ↦ { 𝑚 ∣ ( 𝑚 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑚 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑚 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑚 ‘ 𝑦 ) ) ) } )
2 vex ⊢ 𝑠 ∈ V
3 ovex ⊢ ( 0 [,] +∞ ) ∈ V
4 mapex ⊢ ( ( 𝑠 ∈ V ∧ ( 0 [,] +∞ ) ∈ V ) → { 𝑚 ∣ 𝑚 : 𝑠 ⟶ ( 0 [,] +∞ ) } ∈ V )
5 2 3 4 mp2an ⊢ { 𝑚 ∣ 𝑚 : 𝑠 ⟶ ( 0 [,] +∞ ) } ∈ V
6 simp1 ⊢ ( ( 𝑚 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑚 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑚 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑚 ‘ 𝑦 ) ) ) → 𝑚 : 𝑠 ⟶ ( 0 [,] +∞ ) )
7 6 ss2abi ⊢ { 𝑚 ∣ ( 𝑚 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑚 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑚 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑚 ‘ 𝑦 ) ) ) } ⊆ { 𝑚 ∣ 𝑚 : 𝑠 ⟶ ( 0 [,] +∞ ) }
8 5 7 ssexi ⊢ { 𝑚 ∣ ( 𝑚 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑚 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑚 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑚 ‘ 𝑦 ) ) ) } ∈ V
9 feq1 ⊢ ( 𝑚 = 𝑀 → ( 𝑚 : 𝑠 ⟶ ( 0 [,] +∞ ) ↔ 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ) )
10 fveq1 ⊢ ( 𝑚 = 𝑀 → ( 𝑚 ‘ ∅ ) = ( 𝑀 ‘ ∅ ) )
11 10 eqeq1d ⊢ ( 𝑚 = 𝑀 → ( ( 𝑚 ‘ ∅ ) = 0 ↔ ( 𝑀 ‘ ∅ ) = 0 ) )
12 fveq1 ⊢ ( 𝑚 = 𝑀 → ( 𝑚 ‘ ∪ 𝑥 ) = ( 𝑀 ‘ ∪ 𝑥 ) )
13 fveq1 ⊢ ( 𝑚 = 𝑀 → ( 𝑚 ‘ 𝑦 ) = ( 𝑀 ‘ 𝑦 ) )
14 13 esumeq2sdv ⊢ ( 𝑚 = 𝑀 → Σ* 𝑦 ∈ 𝑥 ( 𝑚 ‘ 𝑦 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) )
15 12 14 eqeq12d ⊢ ( 𝑚 = 𝑀 → ( ( 𝑚 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑚 ‘ 𝑦 ) ↔ ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) )
16 15 imbi2d ⊢ ( 𝑚 = 𝑀 → ( ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑚 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑚 ‘ 𝑦 ) ) ↔ ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) )
17 16 ralbidv ⊢ ( 𝑚 = 𝑀 → ( ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑚 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑚 ‘ 𝑦 ) ) ↔ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) )
18 9 11 17 3anbi123d ⊢ ( 𝑚 = 𝑀 → ( ( 𝑚 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑚 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑚 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑚 ‘ 𝑦 ) ) ) ↔ ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) ) )
19 1 8 18 abfmpunirn ⊢ ( 𝑀 ∈ ∪ ran measures ↔ ( 𝑀 ∈ V ∧ ∃ 𝑠 ∈ ∪ ran sigAlgebra ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) ) )
20 19 simprbi ⊢ ( 𝑀 ∈ ∪ ran measures → ∃ 𝑠 ∈ ∪ ran sigAlgebra ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) )
21 fdm ⊢ ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) → dom 𝑀 = 𝑠 )
22 21 3ad2ant1 ⊢ ( ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) → dom 𝑀 = 𝑠 )
23 22 adantl ⊢ ( ( 𝑠 ∈ ∪ ran sigAlgebra ∧ ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) ) → dom 𝑀 = 𝑠 )
24 simpl ⊢ ( ( 𝑠 ∈ ∪ ran sigAlgebra ∧ ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) ) → 𝑠 ∈ ∪ ran sigAlgebra )
25 23 24 eqeltrd ⊢ ( ( 𝑠 ∈ ∪ ran sigAlgebra ∧ ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) ) → dom 𝑀 ∈ ∪ ran sigAlgebra )
26 simp1 ⊢ ( ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) → 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) )
27 feq2 ⊢ ( dom 𝑀 = 𝑠 → ( 𝑀 : dom 𝑀 ⟶ ( 0 [,] +∞ ) ↔ 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ) )
28 27 biimpar ⊢ ( ( dom 𝑀 = 𝑠 ∧ 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ) → 𝑀 : dom 𝑀 ⟶ ( 0 [,] +∞ ) )
29 22 26 28 syl2anc ⊢ ( ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) → 𝑀 : dom 𝑀 ⟶ ( 0 [,] +∞ ) )
30 simp2 ⊢ ( ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) → ( 𝑀 ‘ ∅ ) = 0 )
31 simp3 ⊢ ( ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) → ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) )
32 pweq ⊢ ( dom 𝑀 = 𝑠 → 𝒫 dom 𝑀 = 𝒫 𝑠 )
33 32 raleqdv ⊢ ( dom 𝑀 = 𝑠 → ( ∀ 𝑥 ∈ 𝒫 dom 𝑀 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ↔ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) )
34 33 biimpar ⊢ ( ( dom 𝑀 = 𝑠 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) → ∀ 𝑥 ∈ 𝒫 dom 𝑀 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) )
35 22 31 34 syl2anc ⊢ ( ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) → ∀ 𝑥 ∈ 𝒫 dom 𝑀 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) )
36 29 30 35 3jca ⊢ ( ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) → ( 𝑀 : dom 𝑀 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 dom 𝑀 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) )
37 36 adantl ⊢ ( ( 𝑠 ∈ ∪ ran sigAlgebra ∧ ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) ) → ( 𝑀 : dom 𝑀 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 dom 𝑀 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) )
38 25 37 jca ⊢ ( ( 𝑠 ∈ ∪ ran sigAlgebra ∧ ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) ) → ( dom 𝑀 ∈ ∪ ran sigAlgebra ∧ ( 𝑀 : dom 𝑀 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 dom 𝑀 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) ) )
39 38 rexlimiva ⊢ ( ∃ 𝑠 ∈ ∪ ran sigAlgebra ( 𝑀 : 𝑠 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 𝑠 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) → ( dom 𝑀 ∈ ∪ ran sigAlgebra ∧ ( 𝑀 : dom 𝑀 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 dom 𝑀 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) ) )
40 20 39 syl ⊢ ( 𝑀 ∈ ∪ ran measures → ( dom 𝑀 ∈ ∪ ran sigAlgebra ∧ ( 𝑀 : dom 𝑀 ⟶ ( 0 [,] +∞ ) ∧ ( 𝑀 ‘ ∅ ) = 0 ∧ ∀ 𝑥 ∈ 𝒫 dom 𝑀 ( ( 𝑥 ≼ ω ∧ Disj 𝑦 ∈ 𝑥 𝑦 ) → ( 𝑀 ‘ ∪ 𝑥 ) = Σ* 𝑦 ∈ 𝑥 ( 𝑀 ‘ 𝑦 ) ) ) ) )