Circular Shifts (aka Cyclic Permutations)
The main inductive
CPermutation relates lists up to circular shifts of their elements.
For example:
CPermutation [a1;a2;a3;a4;a5] [a4;a5;a1;a2;a3]
Note: Terminology does not seem to be strongly fixed in English. For the record, it is "permutations circulaires" in French.