2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/228601In this paper we have compute the Mobius category and the Mobius function of the combinatorial inverse monoid IO3 of all order preserving partial bijections on the set M3={1,2,3}. This category is the reduced standard division category CF(IO3) relative to an idempotent transversal F of the D-classes of IO3.16 pages,exposed on 1st "European Conference on Computer Sciences & Applications" - XA2006, Timisoara, RomaniaRings and Algebrastext