Description: Define reflexive relation; relation R is reflexive over the set A iff A. x e. A x R x . (Contributed by David A. Wheeler, 1-Dec-2019)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-reflexive | |- ( R Reflexive A <-> ( R C_ ( A X. A ) /\ A. x e. A x R x ) )  | 
				
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 0 | cR | |- R  | 
						|
| 1 | cA | |- A  | 
						|
| 2 | 1 0 | wreflexive | |- R Reflexive A  | 
						
| 3 | 1 1 | cxp | |- ( A X. A )  | 
						
| 4 | 0 3 | wss | |- R C_ ( A X. A )  | 
						
| 5 | vx | |- x  | 
						|
| 6 | 5 | cv | |- x  | 
						
| 7 | 6 6 0 | wbr | |- x R x  | 
						
| 8 | 7 5 1 | wral | |- A. x e. A x R x  | 
						
| 9 | 4 8 | wa | |- ( R C_ ( A X. A ) /\ A. x e. A x R x )  | 
						
| 10 | 2 9 | wb | |- ( R Reflexive A <-> ( R C_ ( A X. A ) /\ A. x e. A x R x ) )  |