Step |
Hyp |
Ref |
Expression |
1 |
|
hoidmv0val.l |
⊢ 𝐿 = ( 𝑥 ∈ Fin ↦ ( 𝑎 ∈ ( ℝ ↑m 𝑥 ) , 𝑏 ∈ ( ℝ ↑m 𝑥 ) ↦ if ( 𝑥 = ∅ , 0 , ∏ 𝑘 ∈ 𝑥 ( vol ‘ ( ( 𝑎 ‘ 𝑘 ) [,) ( 𝑏 ‘ 𝑘 ) ) ) ) ) ) |
2 |
|
hoidmv0val.a |
⊢ ( 𝜑 → 𝐴 : ∅ ⟶ ℝ ) |
3 |
|
hoidmv0val.b |
⊢ ( 𝜑 → 𝐵 : ∅ ⟶ ℝ ) |
4 |
|
0fin |
⊢ ∅ ∈ Fin |
5 |
4
|
a1i |
⊢ ( 𝜑 → ∅ ∈ Fin ) |
6 |
1 2 3 5
|
hoidmvval |
⊢ ( 𝜑 → ( 𝐴 ( 𝐿 ‘ ∅ ) 𝐵 ) = if ( ∅ = ∅ , 0 , ∏ 𝑘 ∈ ∅ ( vol ‘ ( ( 𝐴 ‘ 𝑘 ) [,) ( 𝐵 ‘ 𝑘 ) ) ) ) ) |
7 |
|
eqid |
⊢ ∅ = ∅ |
8 |
|
iftrue |
⊢ ( ∅ = ∅ → if ( ∅ = ∅ , 0 , ∏ 𝑘 ∈ ∅ ( vol ‘ ( ( 𝐴 ‘ 𝑘 ) [,) ( 𝐵 ‘ 𝑘 ) ) ) ) = 0 ) |
9 |
7 8
|
ax-mp |
⊢ if ( ∅ = ∅ , 0 , ∏ 𝑘 ∈ ∅ ( vol ‘ ( ( 𝐴 ‘ 𝑘 ) [,) ( 𝐵 ‘ 𝑘 ) ) ) ) = 0 |
10 |
9
|
a1i |
⊢ ( 𝜑 → if ( ∅ = ∅ , 0 , ∏ 𝑘 ∈ ∅ ( vol ‘ ( ( 𝐴 ‘ 𝑘 ) [,) ( 𝐵 ‘ 𝑘 ) ) ) ) = 0 ) |
11 |
6 10
|
eqtrd |
⊢ ( 𝜑 → ( 𝐴 ( 𝐿 ‘ ∅ ) 𝐵 ) = 0 ) |