| Step | Hyp | Ref | Expression | 
						
							| 1 |  | mbfmptcl.1 | ⊢ ( 𝜑  →  ( 𝑥  ∈  𝐴  ↦  𝐵 )  ∈  MblFn ) | 
						
							| 2 |  | mbfmptcl.2 | ⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐴 )  →  𝐵  ∈  𝑉 ) | 
						
							| 3 |  | mbff | ⊢ ( ( 𝑥  ∈  𝐴  ↦  𝐵 )  ∈  MblFn  →  ( 𝑥  ∈  𝐴  ↦  𝐵 ) : dom  ( 𝑥  ∈  𝐴  ↦  𝐵 ) ⟶ ℂ ) | 
						
							| 4 | 1 3 | syl | ⊢ ( 𝜑  →  ( 𝑥  ∈  𝐴  ↦  𝐵 ) : dom  ( 𝑥  ∈  𝐴  ↦  𝐵 ) ⟶ ℂ ) | 
						
							| 5 | 2 | ralrimiva | ⊢ ( 𝜑  →  ∀ 𝑥  ∈  𝐴 𝐵  ∈  𝑉 ) | 
						
							| 6 |  | dmmptg | ⊢ ( ∀ 𝑥  ∈  𝐴 𝐵  ∈  𝑉  →  dom  ( 𝑥  ∈  𝐴  ↦  𝐵 )  =  𝐴 ) | 
						
							| 7 | 5 6 | syl | ⊢ ( 𝜑  →  dom  ( 𝑥  ∈  𝐴  ↦  𝐵 )  =  𝐴 ) | 
						
							| 8 | 7 | feq2d | ⊢ ( 𝜑  →  ( ( 𝑥  ∈  𝐴  ↦  𝐵 ) : dom  ( 𝑥  ∈  𝐴  ↦  𝐵 ) ⟶ ℂ  ↔  ( 𝑥  ∈  𝐴  ↦  𝐵 ) : 𝐴 ⟶ ℂ ) ) | 
						
							| 9 | 4 8 | mpbid | ⊢ ( 𝜑  →  ( 𝑥  ∈  𝐴  ↦  𝐵 ) : 𝐴 ⟶ ℂ ) | 
						
							| 10 | 9 | fvmptelcdm | ⊢ ( ( 𝜑  ∧  𝑥  ∈  𝐴 )  →  𝐵  ∈  ℂ ) |