| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ovnovollem2.a | ⊢ ( 𝜑  →  𝐴  ∈  𝑉 ) | 
						
							| 2 |  | ovnovollem2.b | ⊢ ( 𝜑  →  𝐵  ∈  𝑊 ) | 
						
							| 3 |  | ovnovollem2.i | ⊢ ( 𝜑  →  𝐼  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ ) ) | 
						
							| 4 |  | ovnovollem2.s | ⊢ ( 𝜑  →  ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 ) ) | 
						
							| 5 |  | ovnovollem2.z | ⊢ ( 𝜑  →  𝑍  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) | 
						
							| 6 |  | ovnovollem2.f | ⊢ 𝐹  =  ( 𝑗  ∈  ℕ  ↦  ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 ) ) | 
						
							| 7 |  | elmapi | ⊢ ( 𝐼  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ )  →  𝐼 : ℕ ⟶ ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } ) ) | 
						
							| 8 | 3 7 | syl | ⊢ ( 𝜑  →  𝐼 : ℕ ⟶ ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } ) ) | 
						
							| 9 | 8 | adantr | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  𝐼 : ℕ ⟶ ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } ) ) | 
						
							| 10 |  | simpr | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  𝑗  ∈  ℕ ) | 
						
							| 11 | 9 10 | ffvelcdmd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( 𝐼 ‘ 𝑗 )  ∈  ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } ) ) | 
						
							| 12 |  | elmapi | ⊢ ( ( 𝐼 ‘ 𝑗 )  ∈  ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  →  ( 𝐼 ‘ 𝑗 ) : { 𝐴 } ⟶ ( ℝ  ×  ℝ ) ) | 
						
							| 13 | 11 12 | syl | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( 𝐼 ‘ 𝑗 ) : { 𝐴 } ⟶ ( ℝ  ×  ℝ ) ) | 
						
							| 14 |  | snidg | ⊢ ( 𝐴  ∈  𝑉  →  𝐴  ∈  { 𝐴 } ) | 
						
							| 15 | 1 14 | syl | ⊢ ( 𝜑  →  𝐴  ∈  { 𝐴 } ) | 
						
							| 16 | 15 | adantr | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  𝐴  ∈  { 𝐴 } ) | 
						
							| 17 | 13 16 | ffvelcdmd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 )  ∈  ( ℝ  ×  ℝ ) ) | 
						
							| 18 | 17 6 | fmptd | ⊢ ( 𝜑  →  𝐹 : ℕ ⟶ ( ℝ  ×  ℝ ) ) | 
						
							| 19 |  | reex | ⊢ ℝ  ∈  V | 
						
							| 20 | 19 19 | xpex | ⊢ ( ℝ  ×  ℝ )  ∈  V | 
						
							| 21 |  | nnex | ⊢ ℕ  ∈  V | 
						
							| 22 | 20 21 | elmap | ⊢ ( 𝐹  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ )  ↔  𝐹 : ℕ ⟶ ( ℝ  ×  ℝ ) ) | 
						
							| 23 | 22 | a1i | ⊢ ( 𝜑  →  ( 𝐹  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ )  ↔  𝐹 : ℕ ⟶ ( ℝ  ×  ℝ ) ) ) | 
						
							| 24 | 18 23 | mpbird | ⊢ ( 𝜑  →  𝐹  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) ) | 
						
							| 25 |  | elsni | ⊢ ( 𝑘  ∈  { 𝐴 }  →  𝑘  =  𝐴 ) | 
						
							| 26 | 25 | fveq2d | ⊢ ( 𝑘  ∈  { 𝐴 }  →  ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 )  =  ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝐴 ) ) | 
						
							| 27 | 26 | adantl | ⊢ ( ( ( 𝜑  ∧  𝑗  ∈  ℕ )  ∧  𝑘  ∈  { 𝐴 } )  →  ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 )  =  ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝐴 ) ) | 
						
							| 28 |  | elmapfun | ⊢ ( ( 𝐼 ‘ 𝑗 )  ∈  ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  →  Fun  ( 𝐼 ‘ 𝑗 ) ) | 
						
							| 29 | 11 28 | syl | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  Fun  ( 𝐼 ‘ 𝑗 ) ) | 
						
							| 30 | 13 | fdmd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  dom  ( 𝐼 ‘ 𝑗 )  =  { 𝐴 } ) | 
						
							| 31 | 30 | eqcomd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  { 𝐴 }  =  dom  ( 𝐼 ‘ 𝑗 ) ) | 
						
							| 32 | 16 31 | eleqtrd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  𝐴  ∈  dom  ( 𝐼 ‘ 𝑗 ) ) | 
						
							| 33 |  | fvco | ⊢ ( ( Fun  ( 𝐼 ‘ 𝑗 )  ∧  𝐴  ∈  dom  ( 𝐼 ‘ 𝑗 ) )  →  ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝐴 )  =  ( [,) ‘ ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 ) ) ) | 
						
							| 34 | 29 32 33 | syl2anc | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝐴 )  =  ( [,) ‘ ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 ) ) ) | 
						
							| 35 | 34 | adantr | ⊢ ( ( ( 𝜑  ∧  𝑗  ∈  ℕ )  ∧  𝑘  ∈  { 𝐴 } )  →  ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝐴 )  =  ( [,) ‘ ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 ) ) ) | 
						
							| 36 |  | id | ⊢ ( 𝑗  ∈  ℕ  →  𝑗  ∈  ℕ ) | 
						
							| 37 |  | fvexd | ⊢ ( 𝑗  ∈  ℕ  →  ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 )  ∈  V ) | 
						
							| 38 | 6 | fvmpt2 | ⊢ ( ( 𝑗  ∈  ℕ  ∧  ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 )  ∈  V )  →  ( 𝐹 ‘ 𝑗 )  =  ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 ) ) | 
						
							| 39 | 36 37 38 | syl2anc | ⊢ ( 𝑗  ∈  ℕ  →  ( 𝐹 ‘ 𝑗 )  =  ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 ) ) | 
						
							| 40 | 39 | eqcomd | ⊢ ( 𝑗  ∈  ℕ  →  ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 )  =  ( 𝐹 ‘ 𝑗 ) ) | 
						
							| 41 | 40 | fveq2d | ⊢ ( 𝑗  ∈  ℕ  →  ( [,) ‘ ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 ) )  =  ( [,) ‘ ( 𝐹 ‘ 𝑗 ) ) ) | 
						
							| 42 | 41 | adantl | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( [,) ‘ ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 ) )  =  ( [,) ‘ ( 𝐹 ‘ 𝑗 ) ) ) | 
						
							| 43 | 18 | ffund | ⊢ ( 𝜑  →  Fun  𝐹 ) | 
						
							| 44 | 43 | adantr | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  Fun  𝐹 ) | 
						
							| 45 | 6 17 | dmmptd | ⊢ ( 𝜑  →  dom  𝐹  =  ℕ ) | 
						
							| 46 | 45 | eqcomd | ⊢ ( 𝜑  →  ℕ  =  dom  𝐹 ) | 
						
							| 47 | 46 | adantr | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ℕ  =  dom  𝐹 ) | 
						
							| 48 | 10 47 | eleqtrd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  𝑗  ∈  dom  𝐹 ) | 
						
							| 49 |  | fvco | ⊢ ( ( Fun  𝐹  ∧  𝑗  ∈  dom  𝐹 )  →  ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  =  ( [,) ‘ ( 𝐹 ‘ 𝑗 ) ) ) | 
						
							| 50 | 44 48 49 | syl2anc | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  =  ( [,) ‘ ( 𝐹 ‘ 𝑗 ) ) ) | 
						
							| 51 | 50 | eqcomd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( [,) ‘ ( 𝐹 ‘ 𝑗 ) )  =  ( ( [,)  ∘  𝐹 ) ‘ 𝑗 ) ) | 
						
							| 52 | 42 51 | eqtrd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( [,) ‘ ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 ) )  =  ( ( [,)  ∘  𝐹 ) ‘ 𝑗 ) ) | 
						
							| 53 | 52 | adantr | ⊢ ( ( ( 𝜑  ∧  𝑗  ∈  ℕ )  ∧  𝑘  ∈  { 𝐴 } )  →  ( [,) ‘ ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 ) )  =  ( ( [,)  ∘  𝐹 ) ‘ 𝑗 ) ) | 
						
							| 54 | 27 35 53 | 3eqtrd | ⊢ ( ( ( 𝜑  ∧  𝑗  ∈  ℕ )  ∧  𝑘  ∈  { 𝐴 } )  →  ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 )  =  ( ( [,)  ∘  𝐹 ) ‘ 𝑗 ) ) | 
						
							| 55 | 54 | ixpeq2dva | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 )  =  X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  𝐹 ) ‘ 𝑗 ) ) | 
						
							| 56 |  | snex | ⊢ { 𝐴 }  ∈  V | 
						
							| 57 |  | fvex | ⊢ ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ∈  V | 
						
							| 58 | 56 57 | ixpconst | ⊢ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  =  ( ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ↑m  { 𝐴 } ) | 
						
							| 59 | 58 | a1i | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  =  ( ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ↑m  { 𝐴 } ) ) | 
						
							| 60 | 55 59 | eqtrd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 )  =  ( ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ↑m  { 𝐴 } ) ) | 
						
							| 61 | 60 | iuneq2dv | ⊢ ( 𝜑  →  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 )  =  ∪  𝑗  ∈  ℕ ( ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ↑m  { 𝐴 } ) ) | 
						
							| 62 |  | nfv | ⊢ Ⅎ 𝑗 𝜑 | 
						
							| 63 | 21 | a1i | ⊢ ( 𝜑  →  ℕ  ∈  V ) | 
						
							| 64 |  | fvexd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ∈  V ) | 
						
							| 65 | 62 63 64 1 | iunmapsn | ⊢ ( 𝜑  →  ∪  𝑗  ∈  ℕ ( ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ↑m  { 𝐴 } )  =  ( ∪  𝑗  ∈  ℕ ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ↑m  { 𝐴 } ) ) | 
						
							| 66 | 61 65 | eqtrd | ⊢ ( 𝜑  →  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 )  =  ( ∪  𝑗  ∈  ℕ ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ↑m  { 𝐴 } ) ) | 
						
							| 67 | 4 66 | sseqtrd | ⊢ ( 𝜑  →  ( 𝐵  ↑m  { 𝐴 } )  ⊆  ( ∪  𝑗  ∈  ℕ ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ↑m  { 𝐴 } ) ) | 
						
							| 68 | 21 57 | iunex | ⊢ ∪  𝑗  ∈  ℕ ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ∈  V | 
						
							| 69 | 68 | a1i | ⊢ ( 𝜑  →  ∪  𝑗  ∈  ℕ ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ∈  V ) | 
						
							| 70 | 56 | a1i | ⊢ ( 𝜑  →  { 𝐴 }  ∈  V ) | 
						
							| 71 | 15 | ne0d | ⊢ ( 𝜑  →  { 𝐴 }  ≠  ∅ ) | 
						
							| 72 | 2 69 70 71 | mapss2 | ⊢ ( 𝜑  →  ( 𝐵  ⊆  ∪  𝑗  ∈  ℕ ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ↔  ( 𝐵  ↑m  { 𝐴 } )  ⊆  ( ∪  𝑗  ∈  ℕ ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  ↑m  { 𝐴 } ) ) ) | 
						
							| 73 | 67 72 | mpbird | ⊢ ( 𝜑  →  𝐵  ⊆  ∪  𝑗  ∈  ℕ ( ( [,)  ∘  𝐹 ) ‘ 𝑗 ) ) | 
						
							| 74 |  | icof | ⊢ [,) : ( ℝ*  ×  ℝ* ) ⟶ 𝒫  ℝ* | 
						
							| 75 | 74 | a1i | ⊢ ( 𝜑  →  [,) : ( ℝ*  ×  ℝ* ) ⟶ 𝒫  ℝ* ) | 
						
							| 76 |  | rexpssxrxp | ⊢ ( ℝ  ×  ℝ )  ⊆  ( ℝ*  ×  ℝ* ) | 
						
							| 77 | 76 | a1i | ⊢ ( 𝜑  →  ( ℝ  ×  ℝ )  ⊆  ( ℝ*  ×  ℝ* ) ) | 
						
							| 78 | 75 77 18 | fcoss | ⊢ ( 𝜑  →  ( [,)  ∘  𝐹 ) : ℕ ⟶ 𝒫  ℝ* ) | 
						
							| 79 | 78 | ffnd | ⊢ ( 𝜑  →  ( [,)  ∘  𝐹 )  Fn  ℕ ) | 
						
							| 80 |  | fniunfv | ⊢ ( ( [,)  ∘  𝐹 )  Fn  ℕ  →  ∪  𝑗  ∈  ℕ ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  =  ∪  ran  ( [,)  ∘  𝐹 ) ) | 
						
							| 81 | 79 80 | syl | ⊢ ( 𝜑  →  ∪  𝑗  ∈  ℕ ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  =  ∪  ran  ( [,)  ∘  𝐹 ) ) | 
						
							| 82 | 73 81 | sseqtrd | ⊢ ( 𝜑  →  𝐵  ⊆  ∪  ran  ( [,)  ∘  𝐹 ) ) | 
						
							| 83 |  | nfcv | ⊢ Ⅎ 𝑗 𝐹 | 
						
							| 84 |  | ressxr | ⊢ ℝ  ⊆  ℝ* | 
						
							| 85 |  | xpss2 | ⊢ ( ℝ  ⊆  ℝ*  →  ( ℝ  ×  ℝ )  ⊆  ( ℝ  ×  ℝ* ) ) | 
						
							| 86 | 84 85 | ax-mp | ⊢ ( ℝ  ×  ℝ )  ⊆  ( ℝ  ×  ℝ* ) | 
						
							| 87 | 86 | a1i | ⊢ ( 𝜑  →  ( ℝ  ×  ℝ )  ⊆  ( ℝ  ×  ℝ* ) ) | 
						
							| 88 | 18 87 | fssd | ⊢ ( 𝜑  →  𝐹 : ℕ ⟶ ( ℝ  ×  ℝ* ) ) | 
						
							| 89 | 83 88 | volicofmpt | ⊢ ( 𝜑  →  ( ( vol  ∘  [,) )  ∘  𝐹 )  =  ( 𝑗  ∈  ℕ  ↦  ( vol ‘ ( ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) [,) ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) ) ) ) ) | 
						
							| 90 | 1 | adantr | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  𝐴  ∈  𝑉 ) | 
						
							| 91 |  | fvexd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 )  ∈  V ) | 
						
							| 92 | 10 91 38 | syl2anc | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( 𝐹 ‘ 𝑗 )  =  ( ( 𝐼 ‘ 𝑗 ) ‘ 𝐴 ) ) | 
						
							| 93 | 92 17 | eqeltrd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( 𝐹 ‘ 𝑗 )  ∈  ( ℝ  ×  ℝ ) ) | 
						
							| 94 |  | 1st2nd2 | ⊢ ( ( 𝐹 ‘ 𝑗 )  ∈  ( ℝ  ×  ℝ )  →  ( 𝐹 ‘ 𝑗 )  =  〈 ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) ,  ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) 〉 ) | 
						
							| 95 | 93 94 | syl | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( 𝐹 ‘ 𝑗 )  =  〈 ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) ,  ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) 〉 ) | 
						
							| 96 | 95 | fveq2d | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( [,) ‘ ( 𝐹 ‘ 𝑗 ) )  =  ( [,) ‘ 〈 ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) ,  ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) 〉 ) ) | 
						
							| 97 |  | df-ov | ⊢ ( ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) [,) ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) )  =  ( [,) ‘ 〈 ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) ,  ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) 〉 ) | 
						
							| 98 | 97 | eqcomi | ⊢ ( [,) ‘ 〈 ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) ,  ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) 〉 )  =  ( ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) [,) ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) ) | 
						
							| 99 | 98 | a1i | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( [,) ‘ 〈 ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) ,  ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) 〉 )  =  ( ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) [,) ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) ) ) | 
						
							| 100 | 50 96 99 | 3eqtrd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( ( [,)  ∘  𝐹 ) ‘ 𝑗 )  =  ( ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) [,) ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) ) ) | 
						
							| 101 | 34 52 100 | 3eqtrd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝐴 )  =  ( ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) [,) ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) ) ) | 
						
							| 102 | 101 | fveq2d | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝐴 ) )  =  ( vol ‘ ( ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) [,) ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) ) ) ) | 
						
							| 103 |  | xp1st | ⊢ ( ( 𝐹 ‘ 𝑗 )  ∈  ( ℝ  ×  ℝ )  →  ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) )  ∈  ℝ ) | 
						
							| 104 | 93 103 | syl | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) )  ∈  ℝ ) | 
						
							| 105 |  | xp2nd | ⊢ ( ( 𝐹 ‘ 𝑗 )  ∈  ( ℝ  ×  ℝ )  →  ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) )  ∈  ℝ ) | 
						
							| 106 | 93 105 | syl | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) )  ∈  ℝ ) | 
						
							| 107 |  | volicore | ⊢ ( ( ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) )  ∈  ℝ  ∧  ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) )  ∈  ℝ )  →  ( vol ‘ ( ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) [,) ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) ) )  ∈  ℝ ) | 
						
							| 108 | 104 106 107 | syl2anc | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( vol ‘ ( ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) [,) ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) ) )  ∈  ℝ ) | 
						
							| 109 | 102 108 | eqeltrd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝐴 ) )  ∈  ℝ ) | 
						
							| 110 | 109 | recnd | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝐴 ) )  ∈  ℂ ) | 
						
							| 111 |  | 2fveq3 | ⊢ ( 𝑘  =  𝐴  →  ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 ) )  =  ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝐴 ) ) ) | 
						
							| 112 | 111 | prodsn | ⊢ ( ( 𝐴  ∈  𝑉  ∧  ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝐴 ) )  ∈  ℂ )  →  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 ) )  =  ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝐴 ) ) ) | 
						
							| 113 | 90 110 112 | syl2anc | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 ) )  =  ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝐴 ) ) ) | 
						
							| 114 | 113 102 | eqtr2d | ⊢ ( ( 𝜑  ∧  𝑗  ∈  ℕ )  →  ( vol ‘ ( ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) [,) ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) ) )  =  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) | 
						
							| 115 | 114 | mpteq2dva | ⊢ ( 𝜑  →  ( 𝑗  ∈  ℕ  ↦  ( vol ‘ ( ( 1st  ‘ ( 𝐹 ‘ 𝑗 ) ) [,) ( 2nd  ‘ ( 𝐹 ‘ 𝑗 ) ) ) ) )  =  ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) | 
						
							| 116 | 89 115 | eqtrd | ⊢ ( 𝜑  →  ( ( vol  ∘  [,) )  ∘  𝐹 )  =  ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) | 
						
							| 117 | 116 | fveq2d | ⊢ ( 𝜑  →  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝐹 ) )  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝐼 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) | 
						
							| 118 | 5 117 | eqtr4d | ⊢ ( 𝜑  →  𝑍  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝐹 ) ) ) | 
						
							| 119 | 82 118 | jca | ⊢ ( 𝜑  →  ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝐹 )  ∧  𝑍  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝐹 ) ) ) ) | 
						
							| 120 |  | coeq2 | ⊢ ( 𝑓  =  𝐹  →  ( [,)  ∘  𝑓 )  =  ( [,)  ∘  𝐹 ) ) | 
						
							| 121 | 120 | rneqd | ⊢ ( 𝑓  =  𝐹  →  ran  ( [,)  ∘  𝑓 )  =  ran  ( [,)  ∘  𝐹 ) ) | 
						
							| 122 | 121 | unieqd | ⊢ ( 𝑓  =  𝐹  →  ∪  ran  ( [,)  ∘  𝑓 )  =  ∪  ran  ( [,)  ∘  𝐹 ) ) | 
						
							| 123 | 122 | sseq2d | ⊢ ( 𝑓  =  𝐹  →  ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ↔  𝐵  ⊆  ∪  ran  ( [,)  ∘  𝐹 ) ) ) | 
						
							| 124 |  | coeq2 | ⊢ ( 𝑓  =  𝐹  →  ( ( vol  ∘  [,) )  ∘  𝑓 )  =  ( ( vol  ∘  [,) )  ∘  𝐹 ) ) | 
						
							| 125 | 124 | fveq2d | ⊢ ( 𝑓  =  𝐹  →  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) )  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝐹 ) ) ) | 
						
							| 126 | 125 | eqeq2d | ⊢ ( 𝑓  =  𝐹  →  ( 𝑍  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) )  ↔  𝑍  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝐹 ) ) ) ) | 
						
							| 127 | 123 126 | anbi12d | ⊢ ( 𝑓  =  𝐹  →  ( ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑍  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) )  ↔  ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝐹 )  ∧  𝑍  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝐹 ) ) ) ) ) | 
						
							| 128 | 127 | rspcev | ⊢ ( ( 𝐹  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ )  ∧  ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝐹 )  ∧  𝑍  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝐹 ) ) ) )  →  ∃ 𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑍  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) ) | 
						
							| 129 | 24 119 128 | syl2anc | ⊢ ( 𝜑  →  ∃ 𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑍  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) ) |