2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/65335The behaviour of Castelnuovo-Mumford regularity under ``geometric'' transformations is not well understood. In this paper we are concerned with examples which will shed some light on certain questions concerning this behaviour.Commutative AlgebraAlgebraic Geometry13D45; 13C40; 13D02; 13D40text