Cancellative relations and matrices
The aim of this paper is to define and study cardinal (direct) and ordinal operations of addition, multiplication, and exponentiation for -ary relational systems. -ary ordered sets are defined as special -ary relational systems by means of properties that seem to suitably generalize reflexivity, antisymmetry, and transitivity from the case of or 3. The class of -ary ordered sets is then closed under the cardinal and ordinal operations.
In this paper we find cardinalities of lattices of topologies of uncountable unars and show that the lattice of topologies of a unar cannor be countably infinite. It is proved that under some finiteness conditions the lattice of topologies of a unar is finite. Furthermore, the relations between the lattice of topologies of an arbitrary unar and its congruence lattice are established.
For an uncountable monounary algebra with cardinality it is proved that has exactly retracts. The case when is countable is also dealt with.
It is well-known that the composition of two functors between categories yields a functor again, whenever it exists. The same is true for functors which preserve in a certain sense the structure of symmetric monoidal categories. Considering small symmetric monoidal categories with an additional structure as objects and the structure preserving functors between them as morphisms one obtains different kinds of functor categories, which are even dt-symmetric categories.
Let and be two pointed sets. Given a family of three maps , this family provides an adequate decomposition of as the orthogonal disjoint union of well-described -invariant subsets. This decomposition is applied to the structure theory of graded involutive algebras, graded quadratic algebras and graded weak -algebras.