Description: Elementhood in the set S of all even coverings of an open set in J . S is an even covering of U if it is a nonempty collection of disjoint open sets in C whose union is the preimage of U , such that each set u e. S is homeomorphic under F to U . (Contributed by Mario Carneiro, 13-Feb-2015)
Ref | Expression | ||
---|---|---|---|
Hypothesis | cvmcov.1 | |
|
Assertion | cvmsval | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cvmcov.1 | |
|
2 | 1 | cvmsi | |
3 | 3anass | |
|
4 | id | |
|
5 | pwexg | |
|
6 | difexg | |
|
7 | rabexg | |
|
8 | 5 6 7 | 3syl | |
9 | imaeq2 | |
|
10 | 9 | eqeq2d | |
11 | oveq2 | |
|
12 | 11 | oveq2d | |
13 | 12 | eleq2d | |
14 | 13 | anbi2d | |
15 | 14 | ralbidv | |
16 | 10 15 | anbi12d | |
17 | 16 | rabbidv | |
18 | 17 1 | fvmptg | |
19 | 4 8 18 | syl2anr | |
20 | 19 | eleq2d | |
21 | unieq | |
|
22 | 21 | eqeq1d | |
23 | difeq1 | |
|
24 | 23 | raleqdv | |
25 | 24 | anbi1d | |
26 | 25 | raleqbi1dv | |
27 | 22 26 | anbi12d | |
28 | 27 | elrab | |
29 | eldifsn | |
|
30 | elpw2g | |
|
31 | 30 | adantr | |
32 | 31 | anbi1d | |
33 | 29 32 | bitrid | |
34 | 33 | anbi1d | |
35 | 28 34 | bitrid | |
36 | 20 35 | bitrd | |
37 | 36 | biimprd | |
38 | 37 | expimpd | |
39 | 3 38 | biimtrid | |
40 | 2 39 | impbid2 | |