Über die halbgeordnete Kategorie der partiellen Endomorphismen einer Algebra
Über Mengen von Derivationen. I
Über Mengen von Derivationen. II
Un modèle de filtres pour l'analyse réelle synthétique
Une autre propriété universelle pour le champ associé
Une généralisation des ensembles énumérés
Unified characterization of exponential objects in TOP, PRTOP and PARATOP
Universal categories
Universal category with limits of finite diagrams
Universal coextensions within a variety.
Universal concrete categories and functors
Universal expansion of semigroup varieties by regular involution.
Universal objects in quasiconstructs
The general theory of J’onsson-classes is generalized to strongly smooth quasiconstructs in such a way that it also allows the construction of universal categories. One example of the theory is the existence of a concrete universal category over every base category. Properties are given which are (under certain conditions) equivalent to the existence of homogeneous universal objects. Thereby, we disprove the existence of a homogeneous C-universal category. The notion of homogeneity is strengthened...
Universality of separoids
A separoid is a symmetric relation defined on disjoint pairs of subsets of a given set such that it is closed as a filter in the canonical partial order induced by the inclusion (i.e., and ). We introduce the notion of homomorphism as a map which preserve the so-called “minimal Radon partitions” and show that separoids, endowed with these maps, admits an embedding from the category of all finite graphs. This proves that separoids constitute a countable universal partial order. Furthermore,...
Using the generic interval
Varieties of finite categories
Varieties of idempotent commutative groupoids
Various categorical approaches to statistical spaces [Book]
Weak alg-universality and -universality of semigroup quasivarieties
In an earlier paper, the authors showed that standard semigroups , and play an important role in the classification of weaker versions of alg-universality of semigroup varieties. This paper shows that quasivarieties generated by and are neither relatively alg-universal nor -universal, while there do exist finite semigroups and generating the same semigroup variety as and respectively and the quasivarieties generated by and/or are quasivar-relatively -alg-universal and -universal...
Weak Homotopy Category of a Category with a Cotriple.