| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cvmlift2.b | ⊢ 𝐵  =  ∪  𝐶 | 
						
							| 2 |  | cvmlift2.f | ⊢ ( 𝜑  →  𝐹  ∈  ( 𝐶  CovMap  𝐽 ) ) | 
						
							| 3 |  | cvmlift2.g | ⊢ ( 𝜑  →  𝐺  ∈  ( ( II  ×t  II )  Cn  𝐽 ) ) | 
						
							| 4 |  | cvmlift2.p | ⊢ ( 𝜑  →  𝑃  ∈  𝐵 ) | 
						
							| 5 |  | cvmlift2.i | ⊢ ( 𝜑  →  ( 𝐹 ‘ 𝑃 )  =  ( 0 𝐺 0 ) ) | 
						
							| 6 |  | cvmlift2.h | ⊢ 𝐻  =  ( ℩ 𝑓  ∈  ( II  Cn  𝐶 ) ( ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑧 𝐺 0 ) )  ∧  ( 𝑓 ‘ 0 )  =  𝑃 ) ) | 
						
							| 7 |  | cvmlift2.k | ⊢ 𝐾  =  ( 𝑥  ∈  ( 0 [,] 1 ) ,  𝑦  ∈  ( 0 [,] 1 )  ↦  ( ( ℩ 𝑓  ∈  ( II  Cn  𝐶 ) ( ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑥 𝐺 𝑧 ) )  ∧  ( 𝑓 ‘ 0 )  =  ( 𝐻 ‘ 𝑥 ) ) ) ‘ 𝑦 ) ) | 
						
							| 8 |  | oveq1 | ⊢ ( 𝑥  =  𝑋  →  ( 𝑥 𝐺 𝑧 )  =  ( 𝑋 𝐺 𝑧 ) ) | 
						
							| 9 | 8 | mpteq2dv | ⊢ ( 𝑥  =  𝑋  →  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑥 𝐺 𝑧 ) )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑋 𝐺 𝑧 ) ) ) | 
						
							| 10 | 9 | eqeq2d | ⊢ ( 𝑥  =  𝑋  →  ( ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑥 𝐺 𝑧 ) )  ↔  ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑋 𝐺 𝑧 ) ) ) ) | 
						
							| 11 |  | fveq2 | ⊢ ( 𝑥  =  𝑋  →  ( 𝐻 ‘ 𝑥 )  =  ( 𝐻 ‘ 𝑋 ) ) | 
						
							| 12 | 11 | eqeq2d | ⊢ ( 𝑥  =  𝑋  →  ( ( 𝑓 ‘ 0 )  =  ( 𝐻 ‘ 𝑥 )  ↔  ( 𝑓 ‘ 0 )  =  ( 𝐻 ‘ 𝑋 ) ) ) | 
						
							| 13 | 10 12 | anbi12d | ⊢ ( 𝑥  =  𝑋  →  ( ( ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑥 𝐺 𝑧 ) )  ∧  ( 𝑓 ‘ 0 )  =  ( 𝐻 ‘ 𝑥 ) )  ↔  ( ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑋 𝐺 𝑧 ) )  ∧  ( 𝑓 ‘ 0 )  =  ( 𝐻 ‘ 𝑋 ) ) ) ) | 
						
							| 14 | 13 | riotabidv | ⊢ ( 𝑥  =  𝑋  →  ( ℩ 𝑓  ∈  ( II  Cn  𝐶 ) ( ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑥 𝐺 𝑧 ) )  ∧  ( 𝑓 ‘ 0 )  =  ( 𝐻 ‘ 𝑥 ) ) )  =  ( ℩ 𝑓  ∈  ( II  Cn  𝐶 ) ( ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑋 𝐺 𝑧 ) )  ∧  ( 𝑓 ‘ 0 )  =  ( 𝐻 ‘ 𝑋 ) ) ) ) | 
						
							| 15 | 14 | fveq1d | ⊢ ( 𝑥  =  𝑋  →  ( ( ℩ 𝑓  ∈  ( II  Cn  𝐶 ) ( ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑥 𝐺 𝑧 ) )  ∧  ( 𝑓 ‘ 0 )  =  ( 𝐻 ‘ 𝑥 ) ) ) ‘ 𝑦 )  =  ( ( ℩ 𝑓  ∈  ( II  Cn  𝐶 ) ( ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑋 𝐺 𝑧 ) )  ∧  ( 𝑓 ‘ 0 )  =  ( 𝐻 ‘ 𝑋 ) ) ) ‘ 𝑦 ) ) | 
						
							| 16 |  | fveq2 | ⊢ ( 𝑦  =  𝑌  →  ( ( ℩ 𝑓  ∈  ( II  Cn  𝐶 ) ( ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑋 𝐺 𝑧 ) )  ∧  ( 𝑓 ‘ 0 )  =  ( 𝐻 ‘ 𝑋 ) ) ) ‘ 𝑦 )  =  ( ( ℩ 𝑓  ∈  ( II  Cn  𝐶 ) ( ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑋 𝐺 𝑧 ) )  ∧  ( 𝑓 ‘ 0 )  =  ( 𝐻 ‘ 𝑋 ) ) ) ‘ 𝑌 ) ) | 
						
							| 17 |  | fvex | ⊢ ( ( ℩ 𝑓  ∈  ( II  Cn  𝐶 ) ( ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑋 𝐺 𝑧 ) )  ∧  ( 𝑓 ‘ 0 )  =  ( 𝐻 ‘ 𝑋 ) ) ) ‘ 𝑌 )  ∈  V | 
						
							| 18 | 15 16 7 17 | ovmpo | ⊢ ( ( 𝑋  ∈  ( 0 [,] 1 )  ∧  𝑌  ∈  ( 0 [,] 1 ) )  →  ( 𝑋 𝐾 𝑌 )  =  ( ( ℩ 𝑓  ∈  ( II  Cn  𝐶 ) ( ( 𝐹  ∘  𝑓 )  =  ( 𝑧  ∈  ( 0 [,] 1 )  ↦  ( 𝑋 𝐺 𝑧 ) )  ∧  ( 𝑓 ‘ 0 )  =  ( 𝐻 ‘ 𝑋 ) ) ) ‘ 𝑌 ) ) |