Abstract:The main result of Romanowska A., Roszkowska B., {On some groupoid modes}, Demonstratio Math. {20} (1987), no. 1--2, 277--290, provides us with an explicit description of the lattice of varieties of differential groupoids. In the present article, we show that this variety is $\Cal Q$-universal, which means that there is no convenient explicit description for the lattice of quasivarieties of differential groupoids. We also find an example of a subvariety of differential groupoids with a finite number of subquasivarieties.
Keywords: mode, differential groupoid, lattice of subquasivarieties, $\Cal Q$-universal quasivariety
AMS Subject Classification: 08C15, 20N02