Metamath Proof Explorer
		
		
		
		Description:  An inference based on the Axiom of Replacement.  Typically, ph
       defines a function from x to y .  (Contributed by NM, 26-Nov-1995)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | zfrep3cl.1 | ⊢ 𝐴  ∈  V | 
					
						|  |  | zfrep3cl.2 | ⊢ ( 𝑥  ∈  𝐴  →  ∃ 𝑧 ∀ 𝑦 ( 𝜑  →  𝑦  =  𝑧 ) ) | 
				
					|  | Assertion | zfrep3cl | ⊢  ∃ 𝑧 ∀ 𝑦 ( 𝑦  ∈  𝑧  ↔  ∃ 𝑥 ( 𝑥  ∈  𝐴  ∧  𝜑 ) ) | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | zfrep3cl.1 | ⊢ 𝐴  ∈  V | 
						
							| 2 |  | zfrep3cl.2 | ⊢ ( 𝑥  ∈  𝐴  →  ∃ 𝑧 ∀ 𝑦 ( 𝜑  →  𝑦  =  𝑧 ) ) | 
						
							| 3 |  | nfcv | ⊢ Ⅎ 𝑥 𝐴 | 
						
							| 4 | 3 1 2 | zfrepclf | ⊢ ∃ 𝑧 ∀ 𝑦 ( 𝑦  ∈  𝑧  ↔  ∃ 𝑥 ( 𝑥  ∈  𝐴  ∧  𝜑 ) ) |