51 citations · 125 across the 28 of their papers we have counts for
6 papers · 1 filter
Associative spectra of graph algebras II. Satisfaction of bracketing identities, spectrum dichotomy
Erkko Lehtonen, Tamás Waldhauser
A necessary and sufficient condition is presented for a graph algebra to satisfy a bracketing identity. The associative spectrum of an arbitrary graph algebra is shown to be either…
Associative spectra of graph algebras I. Foundations, undirected graphs, antiassociative graphs
Erkko Lehtonen, Tamás Waldhauser
Associative spectra of graph algebras are examined with the help of homomorphisms of DFS trees. Undirected graphs are classified according to the associative spectra of their graph…
Polymorphism-homogeneity and universal algebraic geometry
Endre Tóth, Tamás Waldhauser
We assign a relational structure to any finite algebra in a canonical way, using solution sets of equations, and we prove that this relational structure is polymorphism-homogeneous…
On centralizers of finite lattices and semilattices
Endre Tóth, Tamás Waldhauser
We study centralizer clones of finite lattices and semilattices. For semilattices, we give two characterizations of the centralizer and also derive formulas for the number of opera…
Multiplication of matrices over lattices
Kamilla Kátai-Urbán, Tamás Waldhauser
We study the multiplication operation of square matrices over lattices. If the underlying lattice is distributive, then matrices form a semigroup; we investigate idempotent and nil…
Solution sets of systems of equations over finite lattices and semilattices
Endre Tóth, Tamás Waldhauser
Solution sets of systems of homogeneous linear equations over fields are characterized as being subspaces, i.e., sets that are closed under linear combinations. Our goal is to char…