| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eqid | ⊢ ( TopOpen ‘ ℂfld )  =  ( TopOpen ‘ ℂfld ) | 
						
							| 2 |  | dfii2 | ⊢ II  =  ( ( topGen ‘ ran  (,) )  ↾t  ( 0 [,] 1 ) ) | 
						
							| 3 |  | unitssre | ⊢ ( 0 [,] 1 )  ⊆  ℝ | 
						
							| 4 | 3 | a1i | ⊢ ( ⊤  →  ( 0 [,] 1 )  ⊆  ℝ ) | 
						
							| 5 |  | iirev | ⊢ ( 𝑥  ∈  ( 0 [,] 1 )  →  ( 1  −  𝑥 )  ∈  ( 0 [,] 1 ) ) | 
						
							| 6 | 5 | adantl | ⊢ ( ( ⊤  ∧  𝑥  ∈  ( 0 [,] 1 ) )  →  ( 1  −  𝑥 )  ∈  ( 0 [,] 1 ) ) | 
						
							| 7 | 1 | cnfldtopon | ⊢ ( TopOpen ‘ ℂfld )  ∈  ( TopOn ‘ ℂ ) | 
						
							| 8 | 7 | a1i | ⊢ ( ⊤  →  ( TopOpen ‘ ℂfld )  ∈  ( TopOn ‘ ℂ ) ) | 
						
							| 9 |  | 1cnd | ⊢ ( ⊤  →  1  ∈  ℂ ) | 
						
							| 10 | 8 8 9 | cnmptc | ⊢ ( ⊤  →  ( 𝑥  ∈  ℂ  ↦  1 )  ∈  ( ( TopOpen ‘ ℂfld )  Cn  ( TopOpen ‘ ℂfld ) ) ) | 
						
							| 11 | 8 | cnmptid | ⊢ ( ⊤  →  ( 𝑥  ∈  ℂ  ↦  𝑥 )  ∈  ( ( TopOpen ‘ ℂfld )  Cn  ( TopOpen ‘ ℂfld ) ) ) | 
						
							| 12 | 1 | subcn | ⊢  −   ∈  ( ( ( TopOpen ‘ ℂfld )  ×t  ( TopOpen ‘ ℂfld ) )  Cn  ( TopOpen ‘ ℂfld ) ) | 
						
							| 13 | 12 | a1i | ⊢ ( ⊤  →   −   ∈  ( ( ( TopOpen ‘ ℂfld )  ×t  ( TopOpen ‘ ℂfld ) )  Cn  ( TopOpen ‘ ℂfld ) ) ) | 
						
							| 14 | 8 10 11 13 | cnmpt12f | ⊢ ( ⊤  →  ( 𝑥  ∈  ℂ  ↦  ( 1  −  𝑥 ) )  ∈  ( ( TopOpen ‘ ℂfld )  Cn  ( TopOpen ‘ ℂfld ) ) ) | 
						
							| 15 | 1 2 2 4 4 6 14 | cnmptre | ⊢ ( ⊤  →  ( 𝑥  ∈  ( 0 [,] 1 )  ↦  ( 1  −  𝑥 ) )  ∈  ( II  Cn  II ) ) | 
						
							| 16 | 15 | mptru | ⊢ ( 𝑥  ∈  ( 0 [,] 1 )  ↦  ( 1  −  𝑥 ) )  ∈  ( II  Cn  II ) |