Our work is a fundamental study of the notion of approximation in Q-categories and in (U, Q)-categories, for a quantale Q and the ultrafilter monad U. We introduce auxiliary, appro...
The eccentric digraph ED(G) of a digraph G represents the binary relation, defined on the vertex set of G, of being `eccentric'; that is, there is an arc from u to v in ED(G)...
: It is well known that, in a topological space, the open sets can be characterized using filter convergence. In ZF (Zermelo-Fraenkel set theory without the Axiom of Choice), we c...
Using a combinatorial characterization of digital convexity based on words, one defines the language of convex words. The complement of this language forms an ideal whose minimal...
In this paper, we present a precise characterization of the existence of a convergent transfer subgraph in an edge colored directed acyclic graph. Based on the characterization, l...