2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/102092Let X be an arbitrary hyperbolic geodesic metric space and let G be a countable non-elementary weakly acylindrical group of isometries of X. We show that the second bounded cohomology group of G with real coefficients or with coefficients in the regular representation is infinite dimensional. The result holds for any subgroup of the mapping class group of a non-exceptional surface of finite type not containing a normal subgroup which virtually split as a direct product.36 pages; Corollary 4.5 corrected, writing improvedGroup TheoryDynamical Systems20F65text