Database SUPPLEMENTARY MATERIAL (USERS' MATHBOXES) Mathbox for Peter Mazsa Partition-Equivalence Theorems pet2  
				
		 
		
			
		 
		Description:   Partition-Equivalence Theorem, with general R  .  This theorem
     (together with pet  and pets  ) is the main result of my investigation
     into set theory, see the comment of pet  .  (Contributed by Peter Mazsa , 24-May-2021)   (Revised by Peter Mazsa , 23-Sep-2021) 
		
			
				
					Ref 
					Expression 
				 
				
					Assertion 
					pet2    ⊢   Disj   R  ⋉    E  -1    ↾   A   ∧     dom  ⁡   R  ⋉    E  -1    ↾   A      /   R  ⋉    E  -1    ↾   A      =  A     ↔   EqvRel  ≀   R  ⋉    E  -1    ↾   A    ∧     dom  ⁡  ≀   R  ⋉    E  -1    ↾   A      /  ≀   R  ⋉    E  -1    ↾   A      =  A          
				 
			
		 
		
				Proof 
				
					
						Step 
						Hyp 
						Ref 
						Expression 
					 
						
							1 
								
							 
							eqvrelqseqdisj5   ⊢   EqvRel  ≀   R  ⋉    E  -1    ↾   A    ∧     dom  ⁡  ≀   R  ⋉    E  -1    ↾   A      /  ≀   R  ⋉    E  -1    ↾   A      =  A     →  Disj   R  ⋉    E  -1    ↾   A        
						
							2 
								1 
							 
							petlem   ⊢   Disj   R  ⋉    E  -1    ↾   A   ∧     dom  ⁡   R  ⋉    E  -1    ↾   A      /   R  ⋉    E  -1    ↾   A      =  A     ↔   EqvRel  ≀   R  ⋉    E  -1    ↾   A    ∧     dom  ⁡  ≀   R  ⋉    E  -1    ↾   A      /  ≀   R  ⋉    E  -1    ↾   A      =  A