Description: Definition of a VI-finite set. (Contributed by Stefan O'Rear, 16-May-2015)
Ref | Expression | ||
---|---|---|---|
Assertion | isfin6 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-fin6 | |
|
2 | 1 | eleq2i | |
3 | relsdom | |
|
4 | 3 | brrelex1i | |
5 | 3 | brrelex1i | |
6 | 4 5 | jaoi | |
7 | breq1 | |
|
8 | id | |
|
9 | 8 | sqxpeqd | |
10 | 8 9 | breq12d | |
11 | 7 10 | orbi12d | |
12 | 6 11 | elab3 | |
13 | 2 12 | bitri | |