Description: A quantifier-free definition of a well-founded relationship. (Contributed by Scott Fenton, 11-Apr-2011)
Ref | Expression | ||
---|---|---|---|
Assertion | dffr5 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eldif | |
|
2 | velpw | |
|
3 | velsn | |
|
4 | 3 | necon3bbii | |
5 | 2 4 | anbi12i | |
6 | 1 5 | bitri | |
7 | brdif | |
|
8 | epel | |
|
9 | vex | |
|
10 | vex | |
|
11 | 9 10 | coep | |
12 | vex | |
|
13 | 9 12 | brcnv | |
14 | 13 | rexbii | |
15 | dfrex2 | |
|
16 | 11 14 15 | 3bitrri | |
17 | 16 | con1bii | |
18 | 8 17 | anbi12i | |
19 | 7 18 | bitri | |
20 | 19 | exbii | |
21 | 10 | elrn | |
22 | df-rex | |
|
23 | 20 21 22 | 3bitr4i | |
24 | 6 23 | imbi12i | |
25 | 24 | albii | |
26 | dfss2 | |
|
27 | df-fr | |
|
28 | 25 26 27 | 3bitr4ri | |