Displaying similar documents to “The lattice of convex subgroupoids of an ordered groupoid.”

On the lattices of quasivarieties of differential groupoids

Aleksandr Kravchenko (2008)

Commentationes Mathematicae Universitatis Carolinae

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The main result of Romanowska A., Roszkowska B., , Demonstratio Math. (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 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. ...