A farewell to Evelyn Nelson
A farewell to Jan Reiterman
Birkhoff's Covariety Theorem without limitations
J. Rutten proved, for accessible endofunctors of , the dual Birkhoff’s Variety Theorem: a collection of -coalgebras is presentable by coequations ( subobjects of cofree coalgebras) iff it is closed under quotients, subcoalgebras, and coproducts. This result is now proved to hold for all endofunctors of provided that coequations are generalized to mean subchains of the cofree-coalgebra chain. For the concept of coequation introduced by H. Porst and the author, which is a subobject of a member...
A farewell to Professor RNDr. Věra Trnková, DrSc.
Cogeneration and minimal realization (Preliminary communication)
Some generalizations of the notions limit and colimit
Free algebras and automata realizations in the language of categories
Limits and colimits in generalized algebraic categories
A farewell to Jan Reiterman
On a representation of semigroups by products of algebras and relations
Completions of concrete categories
On pure quotients and pure subobjects
In the theory of accessible categories, pure subobjects, i.e. filtered colimits of split monomorphisms, play an important role. Here we investigate pure quotients, i.e., filtered colimits of split epimorphisms. For example, in abelian, finitely accessible categories, these are precisely the cokernels of pure subobjects, and pure subobjects are precisely the kernels of pure quotients.
On congruence lattices in a category
Reflections in locally presentable categories
The category of uniform spaces as a completion of the category of metric spaces
A criterion for the existence of an initial completion of a concrete category universal w.r.tḟinite products and subobjects is presented. For metric spaces and uniformly continuous maps this completion is the category of uniform spaces.
A remark on accessible and axiomatizable categories
For categories with equalizers the concepts ``accessible'' and ``axiomatizable'' are equivalent. This results is proved under (in fact, is equivalent to) the large-cardinal Vopěnka's principle.
Cartesian closed categories, quasitopoi and topological universes
What to embed into a Cartesian closed topological category (Preliminary communication)
Cartesian closed hull for metric spaces
Remarks on flows in network with short paths
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