Description: Quantifier-free definition of class intersection. (Contributed by Scott Fenton, 13-Apr-2018)
Ref | Expression | ||
---|---|---|---|
Assertion | dfint3 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dfint2 | |
|
2 | ralnex | |
|
3 | vex | |
|
4 | vex | |
|
5 | 3 4 | brcnv | |
6 | brv | |
|
7 | brdif | |
|
8 | 6 7 | mpbiran | |
9 | 5 8 | bitr2i | |
10 | 9 | con1bii | |
11 | epel | |
|
12 | 10 11 | bitr2i | |
13 | 12 | ralbii | |
14 | eldif | |
|
15 | 4 14 | mpbiran | |
16 | 4 | elima | |
17 | 15 16 | xchbinx | |
18 | 2 13 17 | 3bitr4ri | |
19 | 18 | abbi2i | |
20 | 1 19 | eqtr4i | |