Description: Value of the opposite category. (Contributed by Mario Carneiro, 2-Jan-2017)
Ref | Expression | ||
---|---|---|---|
Hypotheses | oppcval.b | |
|
oppcval.h | |
||
oppcval.x | |
||
oppcval.o | |
||
Assertion | oppcval | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | oppcval.b | |
|
2 | oppcval.h | |
|
3 | oppcval.x | |
|
4 | oppcval.o | |
|
5 | elex | |
|
6 | id | |
|
7 | fveq2 | |
|
8 | 7 2 | eqtr4di | |
9 | 8 | tposeqd | |
10 | 9 | opeq2d | |
11 | 6 10 | oveq12d | |
12 | fveq2 | |
|
13 | 12 1 | eqtr4di | |
14 | 13 | sqxpeqd | |
15 | fveq2 | |
|
16 | 15 3 | eqtr4di | |
17 | 16 | oveqd | |
18 | 17 | tposeqd | |
19 | 14 13 18 | mpoeq123dv | |
20 | 19 | opeq2d | |
21 | 11 20 | oveq12d | |
22 | df-oppc | |
|
23 | ovex | |
|
24 | 21 22 23 | fvmpt | |
25 | 5 24 | syl | |
26 | 4 25 | eqtrid | |