Metamath Proof Explorer
		
		
		
		Description:  A unary (endo)function on a set X .  (Contributed by AV, 15-May-2024)
		
			
				
					|  |  | Ref | Expression | 
				
					|  | Assertion | 1aryfvalel | ⊢  ( 𝑋  ∈  𝑉  →  ( 𝐹  ∈  ( 1 -aryF  𝑋 )  ↔  𝐹 : ( 𝑋  ↑m  { 0 } ) ⟶ 𝑋 ) ) | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 1nn0 | ⊢ 1  ∈  ℕ0 | 
						
							| 2 |  | fzo01 | ⊢ ( 0 ..^ 1 )  =  { 0 } | 
						
							| 3 | 2 | eqcomi | ⊢ { 0 }  =  ( 0 ..^ 1 ) | 
						
							| 4 | 3 | naryfvalel | ⊢ ( ( 1  ∈  ℕ0  ∧  𝑋  ∈  𝑉 )  →  ( 𝐹  ∈  ( 1 -aryF  𝑋 )  ↔  𝐹 : ( 𝑋  ↑m  { 0 } ) ⟶ 𝑋 ) ) | 
						
							| 5 | 1 4 | mpan | ⊢ ( 𝑋  ∈  𝑉  →  ( 𝐹  ∈  ( 1 -aryF  𝑋 )  ↔  𝐹 : ( 𝑋  ↑m  { 0 } ) ⟶ 𝑋 ) ) |