Metamath Proof Explorer
		
		
		
		Description:  Moore closure preserves subset ordering.  Deduction form of mrcss .
       (Contributed by David Moews, 1-May-2017)
		
			
				
					 | 
					 | 
					Ref | 
					Expression | 
				
					
						 | 
						Hypotheses | 
						mrcssd.1 | 
						⊢ ( 𝜑  →  𝐴  ∈  ( Moore ‘ 𝑋 ) )  | 
					
					
						 | 
						 | 
						mrcssd.2 | 
						⊢ 𝑁  =  ( mrCls ‘ 𝐴 )  | 
					
					
						 | 
						 | 
						mrcssd.3 | 
						⊢ ( 𝜑  →  𝑈  ⊆  𝑉 )  | 
					
					
						 | 
						 | 
						mrcssd.4 | 
						⊢ ( 𝜑  →  𝑉  ⊆  𝑋 )  | 
					
				
					 | 
					Assertion | 
					mrcssd | 
					⊢  ( 𝜑  →  ( 𝑁 ‘ 𝑈 )  ⊆  ( 𝑁 ‘ 𝑉 ) )  | 
				
			
		
		
			
				Proof
				
					
						| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							mrcssd.1 | 
							⊢ ( 𝜑  →  𝐴  ∈  ( Moore ‘ 𝑋 ) )  | 
						
						
							| 2 | 
							
								
							 | 
							mrcssd.2 | 
							⊢ 𝑁  =  ( mrCls ‘ 𝐴 )  | 
						
						
							| 3 | 
							
								
							 | 
							mrcssd.3 | 
							⊢ ( 𝜑  →  𝑈  ⊆  𝑉 )  | 
						
						
							| 4 | 
							
								
							 | 
							mrcssd.4 | 
							⊢ ( 𝜑  →  𝑉  ⊆  𝑋 )  | 
						
						
							| 5 | 
							
								2
							 | 
							mrcss | 
							⊢ ( ( 𝐴  ∈  ( Moore ‘ 𝑋 )  ∧  𝑈  ⊆  𝑉  ∧  𝑉  ⊆  𝑋 )  →  ( 𝑁 ‘ 𝑈 )  ⊆  ( 𝑁 ‘ 𝑉 ) )  | 
						
						
							| 6 | 
							
								1 3 4 5
							 | 
							syl3anc | 
							⊢ ( 𝜑  →  ( 𝑁 ‘ 𝑈 )  ⊆  ( 𝑁 ‘ 𝑉 ) )  |