Description: Permutation law for three-place congruence. (Contributed by Scott Fenton, 5-Oct-2013)
Ref | Expression | ||
---|---|---|---|
Assertion | cgr3permute3 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | id | |
|
2 | 3simpa | |
|
3 | 3simpa | |
|
4 | cgrcomlr | |
|
5 | 1 2 3 4 | syl3an | |
6 | 3simpb | |
|
7 | 3simpb | |
|
8 | cgrcomlr | |
|
9 | 1 6 7 8 | syl3an | |
10 | 5 9 | 3anbi12d | |
11 | 3anrot | |
|
12 | 10 11 | bitr4di | |
13 | brcgr3 | |
|
14 | biid | |
|
15 | 3anrot | |
|
16 | 3anrot | |
|
17 | brcgr3 | |
|
18 | 14 15 16 17 | syl3anb | |
19 | 12 13 18 | 3bitr4d | |