Metamath Proof Explorer
		
		
		
		Description:  The monoid of endofunctions on a finite set A is finite.
       (Contributed by AV, 27-Jan-2024)
		
			
				
					|  |  | Ref | Expression | 
					
						|  | Hypotheses | efmndbas.g | ⊢ 𝐺  =  ( EndoFMnd ‘ 𝐴 ) | 
					
						|  |  | efmndbas.b | ⊢ 𝐵  =  ( Base ‘ 𝐺 ) | 
				
					|  | Assertion | efmndbasfi | ⊢  ( 𝐴  ∈  Fin  →  𝐵  ∈  Fin ) | 
			
		
		
			
				Proof
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 1 |  | efmndbas.g | ⊢ 𝐺  =  ( EndoFMnd ‘ 𝐴 ) | 
						
							| 2 |  | efmndbas.b | ⊢ 𝐵  =  ( Base ‘ 𝐺 ) | 
						
							| 3 | 1 2 | efmndbas | ⊢ 𝐵  =  ( 𝐴  ↑m  𝐴 ) | 
						
							| 4 |  | mapfi | ⊢ ( ( 𝐴  ∈  Fin  ∧  𝐴  ∈  Fin )  →  ( 𝐴  ↑m  𝐴 )  ∈  Fin ) | 
						
							| 5 | 4 | anidms | ⊢ ( 𝐴  ∈  Fin  →  ( 𝐴  ↑m  𝐴 )  ∈  Fin ) | 
						
							| 6 | 3 5 | eqeltrid | ⊢ ( 𝐴  ∈  Fin  →  𝐵  ∈  Fin ) |