On the complexity of the lattices of subvarieties and congruences. II. Differential groupoids and unary algebras

A. V. Kravchenko, M. V. Schwidefsky
2020 Sibirskie Elektronnye Matematicheskie Izvestiya  
We prove that certain lattices can be represented as the lattices of relative subvarieties and relative congruences of differential groupoids and unary algebras. This representation result implies that there are continuum many quasivarieties of differential groupoids such that the sets of isomorphism types of finite sublattices of their lattices of relative subvarieties and congruences are not computable. A similar result is obtained for unary algebras and their lattices of relative
more » ... elative congruences. Kravchenko, A.M., Schwidefsky, M.V., On the complexity of the lattices of subvarieties and congruences. II. Differential groupoids and unary algebras.
doi:10.33048/semi.2020.17.054 fatcat:q5m4ckyrdbc3vlttngmzaernee