Description: The first component of an arrow is the ordered pair of domain and codomain. (Contributed by Mario Carneiro, 11-Jan-2017)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | arwrcl.a | |- A = ( Arrow ` C )  | 
					|
| Assertion | arwrcl | |- ( F e. A -> C e. Cat )  | 
				
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | arwrcl.a | |- A = ( Arrow ` C )  | 
						|
| 2 | df-arw | |- Arrow = ( c e. Cat |-> U. ran ( HomA ` c ) )  | 
						|
| 3 | 2 | dmmptss | |- dom Arrow C_ Cat  | 
						
| 4 | elfvdm | |- ( F e. ( Arrow ` C ) -> C e. dom Arrow )  | 
						|
| 5 | 4 1 | eleq2s | |- ( F e. A -> C e. dom Arrow )  | 
						
| 6 | 3 5 | sselid | |- ( F e. A -> C e. Cat )  |