Description: Transitivity induction of subsets, lemma for nacsfix . (Contributed by Stefan O'Rear, 4-Apr-2015)
Ref | Expression | ||
---|---|---|---|
Assertion | incssnn0 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | fveq2 | |
|
2 | 1 | sseq2d | |
3 | 2 | imbi2d | |
4 | fveq2 | |
|
5 | 4 | sseq2d | |
6 | 5 | imbi2d | |
7 | fveq2 | |
|
8 | 7 | sseq2d | |
9 | 8 | imbi2d | |
10 | fveq2 | |
|
11 | 10 | sseq2d | |
12 | 11 | imbi2d | |
13 | ssid | |
|
14 | 13 | 2a1i | |
15 | eluznn0 | |
|
16 | 15 | ancoms | |
17 | fveq2 | |
|
18 | fvoveq1 | |
|
19 | 17 18 | sseq12d | |
20 | 19 | rspcv | |
21 | 16 20 | syl | |
22 | 21 | expimpd | |
23 | 22 | ancomsd | |
24 | sstr2 | |
|
25 | 24 | com12 | |
26 | 23 25 | syl6 | |
27 | 26 | a2d | |
28 | 3 6 9 12 14 27 | uzind4 | |
29 | 28 | com12 | |
30 | 29 | 3impia | |