| Step | Hyp | Ref | Expression | 
						
							| 1 |  | om1bas.o | ⊢ 𝑂  =  ( 𝐽  Ω1  𝑌 ) | 
						
							| 2 |  | om1bas.j | ⊢ ( 𝜑  →  𝐽  ∈  ( TopOn ‘ 𝑋 ) ) | 
						
							| 3 |  | om1bas.y | ⊢ ( 𝜑  →  𝑌  ∈  𝑋 ) | 
						
							| 4 |  | om1opn.k | ⊢ 𝐾  =  ( TopOpen ‘ 𝑂 ) | 
						
							| 5 |  | om1opn.b | ⊢ ( 𝜑  →  𝐵  =  ( Base ‘ 𝑂 ) ) | 
						
							| 6 |  | eqid | ⊢ ( Base ‘ 𝑂 )  =  ( Base ‘ 𝑂 ) | 
						
							| 7 |  | eqid | ⊢ ( TopSet ‘ 𝑂 )  =  ( TopSet ‘ 𝑂 ) | 
						
							| 8 | 6 7 | topnval | ⊢ ( ( TopSet ‘ 𝑂 )  ↾t  ( Base ‘ 𝑂 ) )  =  ( TopOpen ‘ 𝑂 ) | 
						
							| 9 | 4 8 | eqtr4i | ⊢ 𝐾  =  ( ( TopSet ‘ 𝑂 )  ↾t  ( Base ‘ 𝑂 ) ) | 
						
							| 10 | 1 2 3 | om1tset | ⊢ ( 𝜑  →  ( 𝐽  ↑ko  II )  =  ( TopSet ‘ 𝑂 ) ) | 
						
							| 11 | 10 5 | oveq12d | ⊢ ( 𝜑  →  ( ( 𝐽  ↑ko  II )  ↾t  𝐵 )  =  ( ( TopSet ‘ 𝑂 )  ↾t  ( Base ‘ 𝑂 ) ) ) | 
						
							| 12 | 9 11 | eqtr4id | ⊢ ( 𝜑  →  𝐾  =  ( ( 𝐽  ↑ko  II )  ↾t  𝐵 ) ) |