Database BASIC ALGEBRAIC STRUCTURES Subring algebras and ideals Subring algebras sraaddg  
				
		 
		
			
		 
		Description:   Additive operation of a subring algebra.  (Contributed by Stefan O'Rear , 27-Nov-2014)   (Revised by Mario Carneiro , 4-Oct-2015)   (Revised by Thierry Arnoux , 16-Jun-2019)   (Revised by AV , 29-Oct-2024) 
		
			
				
					Ref 
					Expression 
				 
					
						Hypotheses 
						srapart.a ⊢  ( 𝜑   →  𝐴   =  ( ( subringAlg  ‘ 𝑊  ) ‘ 𝑆  ) )  
					
						srapart.s ⊢  ( 𝜑   →  𝑆   ⊆  ( Base ‘ 𝑊  ) )  
				
					Assertion 
					sraaddg ⊢   ( 𝜑   →  ( +g  ‘ 𝑊  )  =  ( +g  ‘ 𝐴  ) )  
			
		 
		
				Proof 
				
					
						Step 
						Hyp 
						Ref 
						Expression 
					 
						
							1 
								
							 
							srapart.a ⊢  ( 𝜑   →  𝐴   =  ( ( subringAlg  ‘ 𝑊  ) ‘ 𝑆  ) )  
						
							2 
								
							 
							srapart.s ⊢  ( 𝜑   →  𝑆   ⊆  ( Base ‘ 𝑊  ) )  
						
							3 
								
							 
							plusgid ⊢  +g   =  Slot  ( +g  ‘ ndx )  
						
							4 
								
							 
							scandxnplusgndx ⊢  ( Scalar ‘ ndx )  ≠  ( +g  ‘ ndx )  
						
							5 
								
							 
							vscandxnplusgndx ⊢  (  · 𝑠   ‘ ndx )  ≠  ( +g  ‘ ndx )  
						
							6 
								
							 
							ipndxnplusgndx ⊢  ( · 𝑖  ‘ ndx )  ≠  ( +g  ‘ ndx )  
						
							7 
								1  2  3  4  5  6 
							 
							sralem ⊢  ( 𝜑   →  ( +g  ‘ 𝑊  )  =  ( +g  ‘ 𝐴  ) )