Database BASIC ALGEBRAIC STRUCTURES Rings Unital rings prdsmulrcl  
				
		 
		
			
		 
		Description:   A structure product of rings has closed binary operation.  (Contributed by Mario Carneiro , 11-Mar-2015)   (Proof shortened by AV , 30-Mar-2025) 
		
			
				
					Ref 
					Expression 
				 
					
						Hypotheses 
						prdsmulrcl.y   ⊢   Y  =  S  ⨉  𝑠 R      
					 
					
						prdsmulrcl.b   ⊢   B  =  Base  Y      
					 
					
						prdsmulrcl.t   ⊢   ·  ˙ =  ⋅  Y      
					 
					
						prdsmulrcl.s    ⊢   φ   →   S  ∈  V         
					 
					
						prdsmulrcl.i    ⊢   φ   →   I  ∈  W         
					 
					
						prdsmulrcl.r    ⊢   φ   →   R  :  I  ⟶  Ring         
					 
					
						prdsmulrcl.f    ⊢   φ   →   F  ∈  B         
					 
					
						prdsmulrcl.g    ⊢   φ   →   G  ∈  B         
					 
				
					Assertion 
					prdsmulrcl    ⊢   φ   →   F  ·  ˙ G ∈  B         
				 
			
		 
		
				Proof 
				
					
						Step 
						Hyp 
						Ref 
						Expression 
					 
						
							1 
								
							 
							prdsmulrcl.y  ⊢   Y  =  S  ⨉  𝑠 R      
						
							2 
								
							 
							prdsmulrcl.b  ⊢   B  =  Base  Y      
						
							3 
								
							 
							prdsmulrcl.t  ⊢   ·  ˙ =  ⋅  Y      
						
							4 
								
							 
							prdsmulrcl.s   ⊢   φ   →   S  ∈  V         
						
							5 
								
							 
							prdsmulrcl.i   ⊢   φ   →   I  ∈  W         
						
							6 
								
							 
							prdsmulrcl.r   ⊢   φ   →   R  :  I  ⟶  Ring         
						
							7 
								
							 
							prdsmulrcl.f   ⊢   φ   →   F  ∈  B         
						
							8 
								
							 
							prdsmulrcl.g   ⊢   φ   →   G  ∈  B         
						
							9 
								
							 
							ringssrng  ⊢   Ring  ⊆  Rng       
						
							10 
								
							 
							fss   ⊢    R  :  I  ⟶  Ring    ∧   Ring  ⊆  Rng     →   R  :  I  ⟶  Rng         
						
							11 
								6  9  10 
							 
							sylancl   ⊢   φ   →   R  :  I  ⟶  Rng         
						
							12 
								1  2  3  4  5  11  7  8 
							 
							prdsmulrngcl   ⊢   φ   →   F  ·  ˙ G ∈  B