Metamath Proof Explorer


Theorem cshwsidrepswmod0

Description: If cyclically shifting a word of length being a prime number results in the word itself, the shift must be either by 0 (modulo the length of the word) or the word must be a "repeated symbol word". (Contributed by AV, 18-May-2018) (Revised by AV, 10-Nov-2018)

Ref Expression
Assertion cshwsidrepswmod0 W Word V W L W cyclShift L = W L mod W = 0 W = W 0 repeatS W

Proof

Step Hyp Ref Expression
1 orc L mod W = 0 L mod W = 0 W = W 0 repeatS W
2 1 2a1d L mod W = 0 W Word V W L W cyclShift L = W L mod W = 0 W = W 0 repeatS W
3 3simpa W Word V W L W Word V W
4 3 ad2antlr L mod W 0 W Word V W L W cyclShift L = W W Word V W
5 simplr3 L mod W 0 W Word V W L W cyclShift L = W L
6 simpll L mod W 0 W Word V W L W cyclShift L = W L mod W 0
7 simpr L mod W 0 W Word V W L W cyclShift L = W W cyclShift L = W
8 cshwsidrepsw W Word V W L L mod W 0 W cyclShift L = W W = W 0 repeatS W
9 8 imp W Word V W L L mod W 0 W cyclShift L = W W = W 0 repeatS W
10 4 5 6 7 9 syl13anc L mod W 0 W Word V W L W cyclShift L = W W = W 0 repeatS W
11 10 olcd L mod W 0 W Word V W L W cyclShift L = W L mod W = 0 W = W 0 repeatS W
12 11 exp31 L mod W 0 W Word V W L W cyclShift L = W L mod W = 0 W = W 0 repeatS W
13 2 12 pm2.61ine W Word V W L W cyclShift L = W L mod W = 0 W = W 0 repeatS W