Description: Given a homotopy from F to G , produce a homotopy from G to F . (Contributed by Jeff Madsen, 2-Sep-2009) (Revised by Mario Carneiro, 23-Feb-2015)
Ref | Expression | ||
---|---|---|---|
Hypotheses | isphtpy.2 | |
|
isphtpy.3 | |
||
phtpycom.6 | |
||
phtpycom.7 | |
||
Assertion | phtpycom | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | isphtpy.2 | |
|
2 | isphtpy.3 | |
|
3 | phtpycom.6 | |
|
4 | phtpycom.7 | |
|
5 | iitopon | |
|
6 | 5 | a1i | |
7 | 1 2 | phtpyhtpy | |
8 | 7 4 | sseldd | |
9 | 6 1 2 3 8 | htpycom | |
10 | 0elunit | |
|
11 | simpr | |
|
12 | oveq1 | |
|
13 | oveq2 | |
|
14 | 13 | oveq2d | |
15 | ovex | |
|
16 | 12 14 3 15 | ovmpo | |
17 | 10 11 16 | sylancr | |
18 | iirev | |
|
19 | 1 2 4 | phtpyi | |
20 | 18 19 | sylan2 | |
21 | 20 | simpld | |
22 | 1 2 4 | phtpy01 | |
23 | 22 | adantr | |
24 | 23 | simpld | |
25 | 17 21 24 | 3eqtrd | |
26 | 1elunit | |
|
27 | oveq1 | |
|
28 | 13 | oveq2d | |
29 | ovex | |
|
30 | 27 28 3 29 | ovmpo | |
31 | 26 11 30 | sylancr | |
32 | 20 | simprd | |
33 | 23 | simprd | |
34 | 31 32 33 | 3eqtrd | |
35 | 2 1 9 25 34 | isphtpyd | |