Metamath Proof Explorer


Theorem measinb

Description: Building a measure restricted to the intersection with a given set. (Contributed by Thierry Arnoux, 25-Dec-2016)

Ref Expression
Assertion measinb ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) → ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ∈ ( measures ‘ 𝑆 ) )

Proof

Step Hyp Ref Expression
1 simpll ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑥𝑆 ) → 𝑀 ∈ ( measures ‘ 𝑆 ) )
2 measbase ( 𝑀 ∈ ( measures ‘ 𝑆 ) → 𝑆 ran sigAlgebra )
3 2 ad2antrr ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑥𝑆 ) → 𝑆 ran sigAlgebra )
4 simpr ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑥𝑆 ) → 𝑥𝑆 )
5 simplr ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑥𝑆 ) → 𝐴𝑆 )
6 inelsiga ( ( 𝑆 ran sigAlgebra ∧ 𝑥𝑆𝐴𝑆 ) → ( 𝑥𝐴 ) ∈ 𝑆 )
7 3 4 5 6 syl3anc ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑥𝑆 ) → ( 𝑥𝐴 ) ∈ 𝑆 )
8 measvxrge0 ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ ( 𝑥𝐴 ) ∈ 𝑆 ) → ( 𝑀 ‘ ( 𝑥𝐴 ) ) ∈ ( 0 [,] +∞ ) )
9 1 7 8 syl2anc ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑥𝑆 ) → ( 𝑀 ‘ ( 𝑥𝐴 ) ) ∈ ( 0 [,] +∞ ) )
10 9 fmpttd ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) → ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) : 𝑆 ⟶ ( 0 [,] +∞ ) )
11 eqidd ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) → ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) = ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) )
12 ineq1 ( 𝑥 = ∅ → ( 𝑥𝐴 ) = ( ∅ ∩ 𝐴 ) )
13 0in ( ∅ ∩ 𝐴 ) = ∅
14 12 13 eqtrdi ( 𝑥 = ∅ → ( 𝑥𝐴 ) = ∅ )
15 14 fveq2d ( 𝑥 = ∅ → ( 𝑀 ‘ ( 𝑥𝐴 ) ) = ( 𝑀 ‘ ∅ ) )
16 15 adantl ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑥 = ∅ ) → ( 𝑀 ‘ ( 𝑥𝐴 ) ) = ( 𝑀 ‘ ∅ ) )
17 measvnul ( 𝑀 ∈ ( measures ‘ 𝑆 ) → ( 𝑀 ‘ ∅ ) = 0 )
18 17 ad2antrr ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑥 = ∅ ) → ( 𝑀 ‘ ∅ ) = 0 )
19 16 18 eqtrd ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑥 = ∅ ) → ( 𝑀 ‘ ( 𝑥𝐴 ) ) = 0 )
20 2 adantr ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) → 𝑆 ran sigAlgebra )
21 0elsiga ( 𝑆 ran sigAlgebra → ∅ ∈ 𝑆 )
22 20 21 syl ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) → ∅ ∈ 𝑆 )
23 0red ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) → 0 ∈ ℝ )
24 11 19 22 23 fvmptd ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) → ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ ∅ ) = 0 )
25 measinblem ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) → ( 𝑀 ‘ ( 𝑧𝐴 ) ) = Σ* 𝑦𝑧 ( 𝑀 ‘ ( 𝑦𝐴 ) ) )
26 eqidd ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) → ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) = ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) )
27 ineq1 ( 𝑥 = 𝑧 → ( 𝑥𝐴 ) = ( 𝑧𝐴 ) )
28 27 adantl ( ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) ∧ 𝑥 = 𝑧 ) → ( 𝑥𝐴 ) = ( 𝑧𝐴 ) )
29 28 fveq2d ( ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) ∧ 𝑥 = 𝑧 ) → ( 𝑀 ‘ ( 𝑥𝐴 ) ) = ( 𝑀 ‘ ( 𝑧𝐴 ) ) )
30 simplll ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) → 𝑀 ∈ ( measures ‘ 𝑆 ) )
31 30 2 syl ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) → 𝑆 ran sigAlgebra )
32 simplr ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) → 𝑧 ∈ 𝒫 𝑆 )
33 simprl ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) → 𝑧 ≼ ω )
34 sigaclcu ( ( 𝑆 ran sigAlgebra ∧ 𝑧 ∈ 𝒫 𝑆𝑧 ≼ ω ) → 𝑧𝑆 )
35 31 32 33 34 syl3anc ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) → 𝑧𝑆 )
36 simpllr ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) → 𝐴𝑆 )
37 inelsiga ( ( 𝑆 ran sigAlgebra ∧ 𝑧𝑆𝐴𝑆 ) → ( 𝑧𝐴 ) ∈ 𝑆 )
38 31 35 36 37 syl3anc ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) → ( 𝑧𝐴 ) ∈ 𝑆 )
39 measvxrge0 ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ ( 𝑧𝐴 ) ∈ 𝑆 ) → ( 𝑀 ‘ ( 𝑧𝐴 ) ) ∈ ( 0 [,] +∞ ) )
40 30 38 39 syl2anc ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) → ( 𝑀 ‘ ( 𝑧𝐴 ) ) ∈ ( 0 [,] +∞ ) )
41 26 29 35 40 fvmptd ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) → ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑧 ) = ( 𝑀 ‘ ( 𝑧𝐴 ) ) )
42 eqidd ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ 𝑦𝑧 ) → ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) = ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) )
43 ineq1 ( 𝑥 = 𝑦 → ( 𝑥𝐴 ) = ( 𝑦𝐴 ) )
44 43 adantl ( ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ 𝑦𝑧 ) ∧ 𝑥 = 𝑦 ) → ( 𝑥𝐴 ) = ( 𝑦𝐴 ) )
45 44 fveq2d ( ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ 𝑦𝑧 ) ∧ 𝑥 = 𝑦 ) → ( 𝑀 ‘ ( 𝑥𝐴 ) ) = ( 𝑀 ‘ ( 𝑦𝐴 ) ) )
46 elpwi ( 𝑧 ∈ 𝒫 𝑆𝑧𝑆 )
47 46 ad2antlr ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ 𝑦𝑧 ) → 𝑧𝑆 )
48 simpr ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ 𝑦𝑧 ) → 𝑦𝑧 )
49 47 48 sseldd ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ 𝑦𝑧 ) → 𝑦𝑆 )
50 simplll ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ 𝑦𝑧 ) → 𝑀 ∈ ( measures ‘ 𝑆 ) )
51 50 2 syl ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ 𝑦𝑧 ) → 𝑆 ran sigAlgebra )
52 simpllr ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ 𝑦𝑧 ) → 𝐴𝑆 )
53 inelsiga ( ( 𝑆 ran sigAlgebra ∧ 𝑦𝑆𝐴𝑆 ) → ( 𝑦𝐴 ) ∈ 𝑆 )
54 51 49 52 53 syl3anc ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ 𝑦𝑧 ) → ( 𝑦𝐴 ) ∈ 𝑆 )
55 measvxrge0 ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ ( 𝑦𝐴 ) ∈ 𝑆 ) → ( 𝑀 ‘ ( 𝑦𝐴 ) ) ∈ ( 0 [,] +∞ ) )
56 50 54 55 syl2anc ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ 𝑦𝑧 ) → ( 𝑀 ‘ ( 𝑦𝐴 ) ) ∈ ( 0 [,] +∞ ) )
57 42 45 49 56 fvmptd ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ 𝑦𝑧 ) → ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑦 ) = ( 𝑀 ‘ ( 𝑦𝐴 ) ) )
58 57 esumeq2dv ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) → Σ* 𝑦𝑧 ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑦 ) = Σ* 𝑦𝑧 ( 𝑀 ‘ ( 𝑦𝐴 ) ) )
59 58 adantr ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) → Σ* 𝑦𝑧 ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑦 ) = Σ* 𝑦𝑧 ( 𝑀 ‘ ( 𝑦𝐴 ) ) )
60 25 41 59 3eqtr4d ( ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) ∧ ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) ) → ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑧 ) = Σ* 𝑦𝑧 ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑦 ) )
61 60 ex ( ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) ∧ 𝑧 ∈ 𝒫 𝑆 ) → ( ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) → ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑧 ) = Σ* 𝑦𝑧 ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑦 ) ) )
62 61 ralrimiva ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) → ∀ 𝑧 ∈ 𝒫 𝑆 ( ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) → ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑧 ) = Σ* 𝑦𝑧 ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑦 ) ) )
63 ismeas ( 𝑆 ran sigAlgebra → ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ∈ ( measures ‘ 𝑆 ) ↔ ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) : 𝑆 ⟶ ( 0 [,] +∞ ) ∧ ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ ∅ ) = 0 ∧ ∀ 𝑧 ∈ 𝒫 𝑆 ( ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) → ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑧 ) = Σ* 𝑦𝑧 ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑦 ) ) ) ) )
64 20 63 syl ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) → ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ∈ ( measures ‘ 𝑆 ) ↔ ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) : 𝑆 ⟶ ( 0 [,] +∞ ) ∧ ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ ∅ ) = 0 ∧ ∀ 𝑧 ∈ 𝒫 𝑆 ( ( 𝑧 ≼ ω ∧ Disj 𝑦𝑧 𝑦 ) → ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑧 ) = Σ* 𝑦𝑧 ( ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ‘ 𝑦 ) ) ) ) )
65 10 24 62 64 mpbir3and ( ( 𝑀 ∈ ( measures ‘ 𝑆 ) ∧ 𝐴𝑆 ) → ( 𝑥𝑆 ↦ ( 𝑀 ‘ ( 𝑥𝐴 ) ) ) ∈ ( measures ‘ 𝑆 ) )