| Step | Hyp | Ref | Expression | 
						
							| 1 |  | ovnovollem3.a | ⊢ ( 𝜑  →  𝐴  ∈  𝑉 ) | 
						
							| 2 |  | ovnovollem3.b | ⊢ ( 𝜑  →  𝐵  ⊆  ℝ ) | 
						
							| 3 |  | ovnovollem3.m | ⊢ 𝑀  =  { 𝑧  ∈  ℝ*  ∣  ∃ 𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ ) ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) } | 
						
							| 4 |  | ovnovollem3.n | ⊢ 𝑁  =  { 𝑧  ∈  ℝ*  ∣  ∃ 𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) } | 
						
							| 5 | 1 | snn0d | ⊢ ( 𝜑  →  { 𝐴 }  ≠  ∅ ) | 
						
							| 6 | 5 | neneqd | ⊢ ( 𝜑  →  ¬  { 𝐴 }  =  ∅ ) | 
						
							| 7 | 6 | iffalsed | ⊢ ( 𝜑  →  if ( { 𝐴 }  =  ∅ ,  0 ,  inf ( 𝑀 ,  ℝ* ,   <  ) )  =  inf ( 𝑀 ,  ℝ* ,   <  ) ) | 
						
							| 8 |  | snfi | ⊢ { 𝐴 }  ∈  Fin | 
						
							| 9 | 8 | a1i | ⊢ ( 𝜑  →  { 𝐴 }  ∈  Fin ) | 
						
							| 10 |  | reex | ⊢ ℝ  ∈  V | 
						
							| 11 | 10 | a1i | ⊢ ( 𝜑  →  ℝ  ∈  V ) | 
						
							| 12 |  | mapss | ⊢ ( ( ℝ  ∈  V  ∧  𝐵  ⊆  ℝ )  →  ( 𝐵  ↑m  { 𝐴 } )  ⊆  ( ℝ  ↑m  { 𝐴 } ) ) | 
						
							| 13 | 11 2 12 | syl2anc | ⊢ ( 𝜑  →  ( 𝐵  ↑m  { 𝐴 } )  ⊆  ( ℝ  ↑m  { 𝐴 } ) ) | 
						
							| 14 | 9 13 3 | ovnval2 | ⊢ ( 𝜑  →  ( ( voln* ‘ { 𝐴 } ) ‘ ( 𝐵  ↑m  { 𝐴 } ) )  =  if ( { 𝐴 }  =  ∅ ,  0 ,  inf ( 𝑀 ,  ℝ* ,   <  ) ) ) | 
						
							| 15 | 2 4 | ovolval5 | ⊢ ( 𝜑  →  ( vol* ‘ 𝐵 )  =  inf ( 𝑁 ,  ℝ* ,   <  ) ) | 
						
							| 16 | 1 | ad2antrr | ⊢ ( ( ( 𝜑  ∧  𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) )  ∧  ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) )  →  𝐴  ∈  𝑉 ) | 
						
							| 17 |  | simplr | ⊢ ( ( ( 𝜑  ∧  𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) )  ∧  ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) )  →  𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) ) | 
						
							| 18 |  | fveq2 | ⊢ ( 𝑛  =  𝑗  →  ( 𝑓 ‘ 𝑛 )  =  ( 𝑓 ‘ 𝑗 ) ) | 
						
							| 19 | 18 | opeq2d | ⊢ ( 𝑛  =  𝑗  →  〈 𝐴 ,  ( 𝑓 ‘ 𝑛 ) 〉  =  〈 𝐴 ,  ( 𝑓 ‘ 𝑗 ) 〉 ) | 
						
							| 20 | 19 | sneqd | ⊢ ( 𝑛  =  𝑗  →  { 〈 𝐴 ,  ( 𝑓 ‘ 𝑛 ) 〉 }  =  { 〈 𝐴 ,  ( 𝑓 ‘ 𝑗 ) 〉 } ) | 
						
							| 21 | 20 | cbvmptv | ⊢ ( 𝑛  ∈  ℕ  ↦  { 〈 𝐴 ,  ( 𝑓 ‘ 𝑛 ) 〉 } )  =  ( 𝑗  ∈  ℕ  ↦  { 〈 𝐴 ,  ( 𝑓 ‘ 𝑗 ) 〉 } ) | 
						
							| 22 |  | simprl | ⊢ ( ( ( 𝜑  ∧  𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) )  ∧  ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) )  →  𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 ) ) | 
						
							| 23 | 11 2 | ssexd | ⊢ ( 𝜑  →  𝐵  ∈  V ) | 
						
							| 24 | 23 | adantr | ⊢ ( ( 𝜑  ∧  𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) )  →  𝐵  ∈  V ) | 
						
							| 25 | 24 | adantr | ⊢ ( ( ( 𝜑  ∧  𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) )  ∧  ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) )  →  𝐵  ∈  V ) | 
						
							| 26 |  | simprr | ⊢ ( ( ( 𝜑  ∧  𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) )  ∧  ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) )  →  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) | 
						
							| 27 | 16 17 21 22 25 26 | ovnovollem1 | ⊢ ( ( ( 𝜑  ∧  𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) )  ∧  ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) )  →  ∃ 𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ ) ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) ) | 
						
							| 28 | 27 | rexlimdva2 | ⊢ ( 𝜑  →  ( ∃ 𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) )  →  ∃ 𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ ) ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) ) ) | 
						
							| 29 | 1 | 3ad2ant1 | ⊢ ( ( 𝜑  ∧  𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ )  ∧  ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) )  →  𝐴  ∈  𝑉 ) | 
						
							| 30 | 23 | 3ad2ant1 | ⊢ ( ( 𝜑  ∧  𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ )  ∧  ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) )  →  𝐵  ∈  V ) | 
						
							| 31 |  | simp2 | ⊢ ( ( 𝜑  ∧  𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ )  ∧  ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) )  →  𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ ) ) | 
						
							| 32 |  | simp3l | ⊢ ( ( 𝜑  ∧  𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ )  ∧  ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) )  →  ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) | 
						
							| 33 |  | fveq2 | ⊢ ( 𝑗  =  𝑛  →  ( 𝑖 ‘ 𝑗 )  =  ( 𝑖 ‘ 𝑛 ) ) | 
						
							| 34 | 33 | coeq2d | ⊢ ( 𝑗  =  𝑛  →  ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) )  =  ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ) | 
						
							| 35 | 34 | fveq1d | ⊢ ( 𝑗  =  𝑛  →  ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  =  ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑘 ) ) | 
						
							| 36 | 35 | ixpeq2dv | ⊢ ( 𝑗  =  𝑛  →  X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  =  X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑘 ) ) | 
						
							| 37 |  | fveq2 | ⊢ ( 𝑘  =  𝑙  →  ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑘 )  =  ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) | 
						
							| 38 | 37 | cbvixpv | ⊢ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑘 )  =  X 𝑙  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) | 
						
							| 39 | 38 | a1i | ⊢ ( 𝑗  =  𝑛  →  X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑘 )  =  X 𝑙  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) | 
						
							| 40 | 36 39 | eqtrd | ⊢ ( 𝑗  =  𝑛  →  X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  =  X 𝑙  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) | 
						
							| 41 | 40 | cbviunv | ⊢ ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  =  ∪  𝑛  ∈  ℕ X 𝑙  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) | 
						
							| 42 | 41 | sseq2i | ⊢ ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ↔  ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑛  ∈  ℕ X 𝑙  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) | 
						
							| 43 | 42 | biimpi | ⊢ ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  →  ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑛  ∈  ℕ X 𝑙  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) | 
						
							| 44 | 32 43 | syl | ⊢ ( ( 𝜑  ∧  𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ )  ∧  ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) )  →  ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑛  ∈  ℕ X 𝑙  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) | 
						
							| 45 |  | simp3r | ⊢ ( ( 𝜑  ∧  𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ )  ∧  ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) )  →  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) | 
						
							| 46 | 35 | fveq2d | ⊢ ( 𝑗  =  𝑛  →  ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) )  =  ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑘 ) ) ) | 
						
							| 47 | 46 | prodeq2ad | ⊢ ( 𝑗  =  𝑛  →  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) )  =  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑘 ) ) ) | 
						
							| 48 | 37 | fveq2d | ⊢ ( 𝑘  =  𝑙  →  ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑘 ) )  =  ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) ) | 
						
							| 49 | 48 | cbvprodv | ⊢ ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑘 ) )  =  ∏ 𝑙  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) | 
						
							| 50 | 49 | a1i | ⊢ ( 𝑗  =  𝑛  →  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑘 ) )  =  ∏ 𝑙  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) ) | 
						
							| 51 | 47 50 | eqtrd | ⊢ ( 𝑗  =  𝑛  →  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) )  =  ∏ 𝑙  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) ) | 
						
							| 52 | 51 | cbvmptv | ⊢ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) )  =  ( 𝑛  ∈  ℕ  ↦  ∏ 𝑙  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) ) | 
						
							| 53 | 52 | fveq2i | ⊢ ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) )  =  ( Σ^ ‘ ( 𝑛  ∈  ℕ  ↦  ∏ 𝑙  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) ) ) | 
						
							| 54 | 53 | eqeq2i | ⊢ ( 𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) )  ↔  𝑧  =  ( Σ^ ‘ ( 𝑛  ∈  ℕ  ↦  ∏ 𝑙  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) ) ) ) | 
						
							| 55 | 54 | biimpi | ⊢ ( 𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) )  →  𝑧  =  ( Σ^ ‘ ( 𝑛  ∈  ℕ  ↦  ∏ 𝑙  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) ) ) ) | 
						
							| 56 | 45 55 | syl | ⊢ ( ( 𝜑  ∧  𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ )  ∧  ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) )  →  𝑧  =  ( Σ^ ‘ ( 𝑛  ∈  ℕ  ↦  ∏ 𝑙  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑛 ) ) ‘ 𝑙 ) ) ) ) ) | 
						
							| 57 |  | fveq2 | ⊢ ( 𝑚  =  𝑛  →  ( 𝑖 ‘ 𝑚 )  =  ( 𝑖 ‘ 𝑛 ) ) | 
						
							| 58 | 57 | fveq1d | ⊢ ( 𝑚  =  𝑛  →  ( ( 𝑖 ‘ 𝑚 ) ‘ 𝐴 )  =  ( ( 𝑖 ‘ 𝑛 ) ‘ 𝐴 ) ) | 
						
							| 59 | 58 | cbvmptv | ⊢ ( 𝑚  ∈  ℕ  ↦  ( ( 𝑖 ‘ 𝑚 ) ‘ 𝐴 ) )  =  ( 𝑛  ∈  ℕ  ↦  ( ( 𝑖 ‘ 𝑛 ) ‘ 𝐴 ) ) | 
						
							| 60 | 29 30 31 44 56 59 | ovnovollem2 | ⊢ ( ( 𝜑  ∧  𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ )  ∧  ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) )  →  ∃ 𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) ) | 
						
							| 61 | 60 | 3exp | ⊢ ( 𝜑  →  ( 𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ )  →  ( ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) )  →  ∃ 𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) ) ) ) | 
						
							| 62 | 61 | rexlimdv | ⊢ ( 𝜑  →  ( ∃ 𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ ) ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) )  →  ∃ 𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) ) ) | 
						
							| 63 | 28 62 | impbid | ⊢ ( 𝜑  →  ( ∃ 𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) )  ↔  ∃ 𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ ) ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) ) ) | 
						
							| 64 | 63 | rabbidv | ⊢ ( 𝜑  →  { 𝑧  ∈  ℝ*  ∣  ∃ 𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) }  =  { 𝑧  ∈  ℝ*  ∣  ∃ 𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ ) ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) } ) | 
						
							| 65 | 4 | a1i | ⊢ ( 𝜑  →  𝑁  =  { 𝑧  ∈  ℝ*  ∣  ∃ 𝑓  ∈  ( ( ℝ  ×  ℝ )  ↑m  ℕ ) ( 𝐵  ⊆  ∪  ran  ( [,)  ∘  𝑓 )  ∧  𝑧  =  ( Σ^ ‘ ( ( vol  ∘  [,) )  ∘  𝑓 ) ) ) } ) | 
						
							| 66 | 3 | a1i | ⊢ ( 𝜑  →  𝑀  =  { 𝑧  ∈  ℝ*  ∣  ∃ 𝑖  ∈  ( ( ( ℝ  ×  ℝ )  ↑m  { 𝐴 } )  ↑m  ℕ ) ( ( 𝐵  ↑m  { 𝐴 } )  ⊆  ∪  𝑗  ∈  ℕ X 𝑘  ∈  { 𝐴 } ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 )  ∧  𝑧  =  ( Σ^ ‘ ( 𝑗  ∈  ℕ  ↦  ∏ 𝑘  ∈  { 𝐴 } ( vol ‘ ( ( [,)  ∘  ( 𝑖 ‘ 𝑗 ) ) ‘ 𝑘 ) ) ) ) ) } ) | 
						
							| 67 | 64 65 66 | 3eqtr4d | ⊢ ( 𝜑  →  𝑁  =  𝑀 ) | 
						
							| 68 | 67 | infeq1d | ⊢ ( 𝜑  →  inf ( 𝑁 ,  ℝ* ,   <  )  =  inf ( 𝑀 ,  ℝ* ,   <  ) ) | 
						
							| 69 | 15 68 | eqtrd | ⊢ ( 𝜑  →  ( vol* ‘ 𝐵 )  =  inf ( 𝑀 ,  ℝ* ,   <  ) ) | 
						
							| 70 | 7 14 69 | 3eqtr4d | ⊢ ( 𝜑  →  ( ( voln* ‘ { 𝐴 } ) ‘ ( 𝐵  ↑m  { 𝐴 } ) )  =  ( vol* ‘ 𝐵 ) ) |