Description: Double restricted quantification over the union of a set and its singleton. (Contributed by Peter Mazsa, 22-Aug-2023)
Ref | Expression | ||
---|---|---|---|
Assertion | disjressuc2 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eqeq1 | |
|
2 | eceq1 | |
|
3 | 2 | ineq1d | |
4 | 3 | eqeq1d | |
5 | 1 4 | orbi12d | |
6 | eqeq2 | |
|
7 | eceq1 | |
|
8 | 7 | ineq2d | |
9 | 8 | eqeq1d | |
10 | 6 9 | orbi12d | |
11 | eqeq1 | |
|
12 | 2 | ineq1d | |
13 | 12 | eqeq1d | |
14 | 11 13 | orbi12d | |
15 | 5 10 14 | 2ralunsn | |
16 | eqid | |
|
17 | 16 | orci | |
18 | 17 | biantru | |
19 | 18 | anbi2i | |
20 | 15 19 | bitr4di | |
21 | eqeq1 | |
|
22 | eqcom | |
|
23 | 21 22 | bitrdi | |
24 | eceq1 | |
|
25 | 24 | ineq1d | |
26 | incom | |
|
27 | 25 26 | eqtrdi | |
28 | 27 | eqeq1d | |
29 | 23 28 | orbi12d | |
30 | 29 | cbvralvw | |
31 | 30 | biimpi | |
32 | 31 | pm4.71i | |
33 | 32 | anbi2i | |
34 | 3anass | |
|
35 | df-3an | |
|
36 | 33 34 35 | 3bitr2ri | |
37 | 20 36 | bitrdi | |
38 | elneq | |
|
39 | 38 | neneqd | |
40 | 39 | biorfd | |
41 | 40 | ralbiia | |
42 | 41 | anbi2i | |
43 | 37 42 | bitr4di | |