Description: A singleton of an irreducible word is an extension sequence. (Contributed by Mario Carneiro, 27-Sep-2015)
Ref | Expression | ||
---|---|---|---|
Hypotheses | efgval.w | |
|
efgval.r | |
||
efgval2.m | |
||
efgval2.t | |
||
efgred.d | |
||
efgred.s | |
||
Assertion | efgs1 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | efgval.w | |
|
2 | efgval.r | |
|
3 | efgval2.m | |
|
4 | efgval2.t | |
|
5 | efgred.d | |
|
6 | efgred.s | |
|
7 | eldifi | |
|
8 | 7 5 | eleq2s | |
9 | 8 | s1cld | |
10 | s1nz | |
|
11 | eldifsn | |
|
12 | 9 10 11 | sylanblrc | |
13 | s1fv | |
|
14 | id | |
|
15 | 13 14 | eqeltrd | |
16 | s1len | |
|
17 | 16 | a1i | |
18 | 17 | oveq2d | |
19 | fzo0 | |
|
20 | 18 19 | eqtrdi | |
21 | rzal | |
|
22 | 20 21 | syl | |
23 | 1 2 3 4 5 6 | efgsdm | |
24 | 12 15 22 23 | syl3anbrc | |