Metamath Proof Explorer
		
		
		
		Description:  Define negated membership as binary relation.  Analogous to df-eprel (the membership relation).  (Contributed by AV, 26-Dec-2021)
		
			
				
					|  |  | Ref | Expression | 
				
					|  | Assertion | df-nelbr | ⊢   _∉   =  { 〈 𝑥 ,  𝑦 〉  ∣  ¬  𝑥  ∈  𝑦 } | 
			
		
		
			
				Detailed syntax breakdown
				
					
						| Step | Hyp | Ref | Expression | 
						
							| 0 |  | cnelbr | ⊢  _∉ | 
						
							| 1 |  | vx | ⊢ 𝑥 | 
						
							| 2 |  | vy | ⊢ 𝑦 | 
						
							| 3 | 1 | cv | ⊢ 𝑥 | 
						
							| 4 | 2 | cv | ⊢ 𝑦 | 
						
							| 5 | 3 4 | wcel | ⊢ 𝑥  ∈  𝑦 | 
						
							| 6 | 5 | wn | ⊢ ¬  𝑥  ∈  𝑦 | 
						
							| 7 | 6 1 2 | copab | ⊢ { 〈 𝑥 ,  𝑦 〉  ∣  ¬  𝑥  ∈  𝑦 } | 
						
							| 8 | 0 7 | wceq | ⊢  _∉   =  { 〈 𝑥 ,  𝑦 〉  ∣  ¬  𝑥  ∈  𝑦 } |