A construction of dual box

Abstract

Let \({\mathtt R}\) be a quasi-hereditary algebra, \({\mathscr F} (\Delta)\)  and \({\mathscr F}(\nabla)\)  its categories of good and cogood modules correspondingly. In [6] these categories were characterized as the categories of representations of some boxes \({\mathscr A}={\mathscr A}_{\Delta}\) and \({\mathscr A}_{\nabla}\). These last are the box theory counterparts of Ringel duality ([8]). We present an implicit construction of the box \({\mathscr B}\) such that \({\mathscr B}-{\mathrm{mo\,}}\) is equivalent to \({\mathscr F}(\nabla)\).