Characterizations of Hamiltonian algebras
Characterizing binary discriminator algebras
The concept of the (dual) binary discriminator was introduced by R. Halas, I. G. Rosenberg and the author in 1999. We study finite algebras having the (dual) discriminator as a term function. In particular, a simple characterization is obtained for such algebras with a majority term function.
Characterizing matrices with -simple image eigenspace in max-min semiring
A matrix is said to have -simple image eigenspace if any eigenvector belonging to the interval is the unique solution of the system in . The main result of this paper is a combinatorial characterization of such matrices in the linear algebra over max-min (fuzzy) semiring. The characterized property is related to and motivated by the general development of tropical linear algebra and interval analysis, as well as the notions of simple image set and weak robustness (or weak stability) that...
Characterizing tolerance trivial finite algebras
An algebra is tolerance trivial if where is the lattice of all tolerances on . If contains a Mal’cev function compatible with each , then is tolerance trivial. We investigate finite algebras satisfying also the converse statement.
Church-Rosser property and decidability of monadic theories of unary algebras
Class preserving mappings of equivalence systems
By an equivalence system is meant a couple where is a non-void set and is an equivalence on . A mapping of an equivalence system into is called a class preserving mapping if for each . We will characterize class preserving mappings by means of permutability of with the equivalence induced by .
Classes of graphs definable by graph algebra identities or quasi-identities
Classi e schemi ideali. Congruenze ideali V
Classification of Maps by Their Membership in Maximal Clones That Contain Minimum and Complement
Clausal relations and C-clones
We introduce a special set of relations called clausal relations. We study a Galois connection Pol-CInv between the set of all finitary operations on a finite set D and the set of clausal relations, which is a restricted version of the Galois connection Pol-Inv. We define C-clones as the Galois closed sets of operations with respect to Pol-CInv and describe the lattice of all C-clones for the Boolean case D = {0,1}. Finally we prove certain results about C-clones over a larger set.
Clifford congruences on generalized quasi-orthodox GV-semigroups
A semigroup S is said to be completely π-regular if for any a ∈ S there exists a positive integer n such that aⁿ is completely regular. A completely π-regular semigroup S is said to be a GV-semigroup if all the regular elements of S are completely regular. The present paper is devoted to the study of generalized quasi-orthodox GV-semigroups and least Clifford congruences on them.
Clone automorphisms and hypersubstitutions.
Clone compatible identities and clone extensions of algebras
Clones closed with respect to permutation groups or transformation semigroups.
Clones, coclones and coconnected spaces.
Clones in topology and algebra.
Clones on regular cardinals
We investigate the structure of the lattice of clones on an infinite set X. We first observe that ultrafilters naturally induce clones; this yields a simple proof of Rosenberg’s theorem: there are maximal (= “precomplete”) clones on a set of size λ. The clones we construct do not contain all unary functions. We then investigate clones that do contain all unary functions. Using a strong negative partition theorem from pcf theory we show that for cardinals λ (in particular, for all successors of...
Closed sets of universal Horn formulas for many-sorted (partial) algebras
Closure properties for relational systems with given endomorphism structure
Cogeneration and minimal realization (Preliminary communication)