Description: Define the set of even permutations on a given set. (Contributed by Stefan O'Rear, 9-Jul-2018)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-evpm | |- pmEven = ( d e. _V |-> ( `' ( pmSgn ` d ) " { 1 } ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 0 | cevpm | |- pmEven | |
| 1 | vd | |- d | |
| 2 | cvv | |- _V | |
| 3 | cpsgn | |- pmSgn | |
| 4 | 1 | cv | |- d | 
| 5 | 4 3 | cfv | |- ( pmSgn ` d ) | 
| 6 | 5 | ccnv | |- `' ( pmSgn ` d ) | 
| 7 | c1 | |- 1 | |
| 8 | 7 | csn |  |-  { 1 } | 
| 9 | 6 8 | cima |  |-  ( `' ( pmSgn ` d ) " { 1 } ) | 
| 10 | 1 2 9 | cmpt |  |-  ( d e. _V |-> ( `' ( pmSgn ` d ) " { 1 } ) ) | 
| 11 | 0 10 | wceq |  |-  pmEven = ( d e. _V |-> ( `' ( pmSgn ` d ) " { 1 } ) ) |