2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/218541We analyze the monodromy action, over the rationals, on the first homology group of the Milnor fiber, for arbitrary subarrangements of Coxeter arrangements. We propose a combinatorial formula for the monodromy action, involving Aomoto complexes in positive characteristic. We verify the formula, in cases A, B and D.23 pages; updated referencesAlgebraic GeometryCombinatorics32S55, 52C35; 20F55, 55N25text