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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...

Weak alg-universality and $Q$ -universality of semigroup quasivarieties

Marie Demlová, Václav Koubek (2005)

Commentationes Mathematicae Universitatis Carolinae

In an earlier paper, the authors showed that standard semigroups $𝐌_{1}$ , $𝐌_{2}$ and $𝐌_{3}$ play an important role in the classification of weaker versions of alg-universality of semigroup varieties. This paper shows that quasivarieties generated by $𝐌_{2}$ and $𝐌_{3}$ are neither relatively alg-universal nor $Q$ -universal, while there do exist finite semigroups $𝐒_{2}$ and $𝐒_{3}$ generating the same semigroup variety as $𝐌_{2}$ and $𝐌_{3}$ respectively and the quasivarieties generated by $𝐒_{2}$ and/or $𝐒_{3}$ are quasivar-relatively $f f$ -alg-universal and $Q$ -universal...

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Stability of algebraic inverse systems, I: Stability, weak stability and the weakly-stable socle

Strong embeddings into categories of algebras over a monad. II.

Strong embeddings into categories of algebras over a monad. I.

The categories of presheaves containing any category of algebras [Book]

The category of totally symmetric quasigroups is binding

The extensive completion of a distributive category.

The infinite minimal rich monoid

The structure of initial completions

Topological categories containing any category of algebras

Universal coextensions within a variety.

Universal concrete categories and functors

Universal expansion of semigroup varieties by regular involution.

Universal objects in quasiconstructs

Weak alg-universality and $Q$ -universality of semigroup quasivarieties

Weakly locally presentable categories

What to embed into a Cartesian closed topological category (Preliminary communication)

Детализации

Currently displaying 61 – 77 of 77