Database SUPPLEMENTARY MATERIAL (USERS' MATHBOXES) Mathbox for Zhi Wang Propositional calculus mpbiran3d  
				
		 
		
			
		 
		Description:   Equivalence with a conjunction one of whose conjuncts is a consequence
         of the other.  Deduction form.  (Contributed by Zhi Wang , 24-Sep-2024) 
		
			
				
					Ref 
					Expression 
				 
					
						Hypotheses 
						mpbiran3d.1 ⊢  ( 𝜑   →  ( 𝜓   ↔  ( 𝜒   ∧  𝜃  ) ) )  
					
						mpbiran3d.2 ⊢  ( ( 𝜑   ∧  𝜒  )  →  𝜃  )  
				
					Assertion 
					mpbiran3d ⊢   ( 𝜑   →  ( 𝜓   ↔  𝜒  ) )  
			
		 
		
				Proof 
				
					
						Step 
						Hyp 
						Ref 
						Expression 
					 
						
							1 
								
							 
							mpbiran3d.1 ⊢  ( 𝜑   →  ( 𝜓   ↔  ( 𝜒   ∧  𝜃  ) ) )  
						
							2 
								
							 
							mpbiran3d.2 ⊢  ( ( 𝜑   ∧  𝜒  )  →  𝜃  )  
						
							3 
								1 
							 
							simprbda ⊢  ( ( 𝜑   ∧  𝜓  )  →  𝜒  )  
						
							4 
								3 
							 
							ex ⊢  ( 𝜑   →  ( 𝜓   →  𝜒  ) )  
						
							5 
								2 
							 
							ex ⊢  ( 𝜑   →  ( 𝜒   →  𝜃  ) )  
						
							6 
								5 
							 
							ancld ⊢  ( 𝜑   →  ( 𝜒   →  ( 𝜒   ∧  𝜃  ) ) )  
						
							7 
								6  1 
							 
							sylibrd ⊢  ( 𝜑   →  ( 𝜒   →  𝜓  ) )  
						
							8 
								4  7 
							 
							impbid ⊢  ( 𝜑   →  ( 𝜓   ↔  𝜒  ) )