Primitive classes of algebras with unary and nullary operations
Realization of small concrete categories by algebras and injective homomorphisms
An algorithm for free algebras
We present an algorithm for constructing the free algebra over a given finite partial algebra in the variety determined by a finite list of equations. The algorithm succeeds whenever the desired free algebra is finite.
Termal groupoids
We investigate the factor of the groupoid of terms through the largest congruence with a given set among its blocks. The set is supposed to be closed for overterms.
Three-variable equations of posets
We find an independent base for three-variable equations of posets.
Constructions over tournaments
We investigate tournaments that are projective in the variety that they generate, and free algebras over partial tournaments in that variety. We prove that the variety determined by three-variable equations of tournaments is not locally finite. We also construct infinitely many finite, pairwise incomparable simple tournaments.
Enumerating left distributive groupoids
The lattice of equational theories. Part II: The lattice of full sets of terms
The lattice of equational theories. Part I: Modular elements
The lattice of equational theories. Part IV: Equational theories of finite algebras
Normal subsets of quasigroups
Upper semicomplements and a definable element in the lattice of groupoid varieties
Algebraicity of endomorphisms of some relational structures
Free groupoids in varieties determined by a short equation
Definability for equational theories of commutative groupoids
We find several large classes of equations with the property that every automorphism of the lattice of equational theories of commutative groupoids fixes any equational theory generated by such equations, and every equational theory generated by finitely many such equations is a definable element of the lattice. We conjecture that the lattice has no non-identical automorphisms.
A note on finite sets of terms closed under subterms and unification
The paper contains two remarks on finite sets of groupoid terms closed under subterms and the application of unifying pairs.
Terms and semiterms
A note on isomorphic varieties
On atoms in lattices of primitive classes
Reduced dimension of primitive classes of universal algebras
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