2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/216240Categorical rings were introduced by Jibladze and Pirashvili in their paper "Third Mac Lane cohomology via categorical rings", Journal of Homotopy and related structures, 2, 2007, 187-216. We call those "2-rings". In these notes we present basic definitions and results regarding 2-modules. This is work in progress.73 pagesCategory TheoryCommutative Algebra18D99text