A category theoretical background for homomorphism theorems
A duality for isotropic median algebras
We establish categorical dualities between varieties of isotropic median algebras and suitable categories of operational and relational topological structures. We follow a general duality theory of B.A. Davey and H. Werner. The duality results are used to describe free isotropic median algebras. If the number of free generators is less than five, the description is detailed.
A new proof of Reiterman's theorem
A note on isomorphic varieties
A note on reflective subcategories defined by partial algebras
Absolutely closed spaces and categories of algebras
Adjointness between theories and strict theories
The categorical concept of a theory for algebras of a given type was foundet by Lawvere in 1963 (see [8]). Hoehnke extended this concept to partial heterogenous algebras in 1976 (see [5]). A partial theory is a dhts-category such that the object class forms a free algebra of type (2,0,0) freely generated by a nonempty set J in the variety determined by the identities ox ≈ o and xo ≈ o, where o and i are the elements selected by the 0-ary operation symbols. If the object class of a dhts-category...
Aggregation operators on partially ordered sets and their categorical foundations
In spite of increasing studies and investigations in the field of aggregation operators, there are two fundamental problems remaining unsolved: aggregation of -fuzzy set-theoretic notions and their justification. In order to solve these problems, we will formulate aggregation operators and their special types on partially ordered sets with universal bounds, and introduce their categories. Furthermore, we will show that there exists a strong connection between the category of aggregation operators...
Algebraic duality of constant algebras
Algebraic theories and varieties of functor algebras
Algebras over theories
An Elementary Characterization of the Category of (Free) Relational Systems.
Automorphisms of categories of free algebras of varieties.
Bijective reflexions and coreflexions of commutative unars
Cartesian closedness in categories of partial algebras.
Categorical equivalences of varieties generated by algebras and
Categories of functors between categories with partial morphisms
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.
Categories of locally diagonal partial algebras.
Central extensions in Mal'tsev varieties.
Centrality and normality in protomodular categories.