Database  
				SUPPLEMENTARY MATERIAL (USERS' MATHBOXES)  
				Mathbox for Peter Mazsa  
				Partition-Equivalence Theorems  
				pet2  
			 
				
		 
		 Metamath Proof Explorer 
		
			
		 
		 
		
		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