Exponentiation without associativity
Function classes and relational constraints stable under compositions with clones
The general Galois theory for functions and relational constraints over arbitrary sets described in the authors' previous paper is refined by imposing algebraic conditions on relations.
Functional representation of preiterative/combinatory formalism
Graphic algebras
Groupoids assigned to relational systems
By a relational system we mean a couple where is a set and is a binary relation on , i.e. . To every directed relational system we assign a groupoid on the same base set where if and only if . We characterize basic properties of by means of identities satisfied by and show how homomorphisms between those groupoids are related to certain homomorphisms of relational systems.
Homogeneous superassociative systems
Homogeneous tolerance spaces
Homomorphic correspondences of relational systems
Homomorphisms and strong homomorphisms of relational structures
Homomorphisms of algebras
A construction of all homomorphisms of an algebra with a finite number of operations into an algebra of the same type is presented that consists in replacing algebras by suitable mono-unary algebras (possibly with some nullary operations) and their homomorphisms by suitable homomorphisms of the corresponding mono-unary algebras. Since a construction of all homomorphisms between two mono-unary algebras is known (see, e.g., [6], [7], [8]), a construction of all homomorphisms of an arbitrary algebra...
Homomorphisms of heterogeneous algebras
A construction of all homomorphisms of a heterogeneous algebra into an algebra of the same type is presented. A relational structure is assigned to any heterogeneous algebra, and homomorphisms between these relational structures make it possible to construct homomorphisms between heterogeneous algebras. Homomorphisms of relational structures can be constructed using homomorphisms of algebras that are described in [11].
Hypergroupes Canoniques Values et Hypervalues-Hypergroupes Fortement et Superieurement Canoniques
Incidence structures of independent sets
Incidence structures of type
Every incidence structure (understood as a triple of sets , ) admits for every positive integer an incidence structure where () consists of all independent -element subsets in () and is determined by some bijections. In the paper such incidence structures are investigated the ’s of which have their incidence graphs of the simple join form. Some concrete illustrations are included with small sets and .
Inclusion properties of the intersection convolution of relations.
Induced isomorphisms of certain ternary semigroups
Infinitary varieties of structures closed under the formation of complex structures
Join-closed and meet-closed subsets in complete lattices
To every subset of a complete lattice we assign subsets , and define join-closed and meet-closed sets in . Some properties of such sets are proved. Join- and meet-closed sets in power-set lattices are characterized. The connections about join-independent (meet-independent) and join-closed (meet-closed) subsets are also presented in this paper.
Konzepte in den triadischen Kontext
Lattice betweenness relation and a generalization of König's lemma