2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/58360If a string is cyclically shifted it will re-appear after a certain number of shifts, which will be called its order. We solve the problem of how many strings exist with a given order. This problem arises in the context of quantum mechanics of spin systems.7 pages, submitted to Discrete Applied Mathematics. More information at http://www.physik.uni-osnabrueck.de/makrosysteme/Mathematical Physicstext