[PDF][PDF] Various properties of various ultrafilters, various graph width parameters, and various connectivity systems

T Fujita - arXiv preprint arXiv, 2024 - researchgate.net
This paper investigates ultrafilters in the context of connectivity systems, defined as pairs (X,
f) where X is a finite set and f is a symmetric submodular function. Ultrafilters, essential in …

Exploring two concepts: branch decomposition and weak ultrafilter on connectivity system

T Fujita - arXiv preprint arXiv:2306.14147, 2023 - arxiv.org
This paper explores two fundamental concepts: branch width and weak ultrafilter. Branch
width is a significant graph width parameter that measures the degree of connectivity in a …

A short note of the relationship between loose tangles and filters

T Fujita - International Journal of Mathematics Trends and …, 2024 - ijmttjournal.org
Tangle, a concept related to graph width parameters, has been defined and studied in graph
theory. It has a dual relationship with branch width. Loose Tangle relaxes the axioms of …

[PDF][PDF] A note on grill and primal: Relationship to branch-width

T Fujita - preprint (researchgate), 2024 - researchgate.net
Graph characteristics are often analyzed using various parameters, with ongoing research
dedicated to exploring these aspects. A filter is a fundamental concept in mathematics …

Quasi-Ultrafilter on the Connectivity System: Its Relationship to Branch-Decomposition

T Fujita - International Journal of Mathematics Trends and …, 2024 - ijmttjournal.org
The exploration of graph width parameters, spanning both graph theory and algebraic
frameworks, has captured substantial attention. Among these, branch width has distinctly …

Compositional algorithms on compositional data: deciding sheaves on presheaves

E Althaus, BM Bumpus, J Fairbanks… - arXiv preprint arXiv …, 2023 - arxiv.org
Algorithmicists are well-aware that fast dynamic programming algorithms are very often the
correct choice when computing on compositional (or even recursive) graphs. Here we …

Generalizing graph decompositions

BM Bumpus - 2021 - theses.gla.ac.uk
The Latin aphorism 'divide et impera'conveys a simple, but central idea in mathematics and
computer science:'split your problem recursively into smaller parts, attack the parts, and …

Various Properties of Various Ultrafilters, Various Graph Width Parameters, and Various Connectivity Systems (with Survey)

T Fujita - arXiv preprint arXiv:2408.02299, 2024 - arxiv.org
This paper investigates ultrafilters in the context of connectivity systems, defined as pairs
$(X, f) $ where $ X $ is a finite set and $ f $ is a symmetric submodular function. Ultrafilters …

[PDF][PDF] Linear-branch-decomposition of digraph

T Fujita - Theory and Applications of Graphs, submitted - researchgate.net
The study of graph width parameters is a well-established field within graph theory.
Recently, numerous researchers have been actively extending undirected width parameters …

[PDF][PDF] Comparing and Computing Parameters for Directed Graphs

C Rehs - 2022 - docserv.uni-duesseldorf.de
The field of undirected graph parameters is a very huge one and has been wellresearched
since the 1980s. A graph parameter, also called width measure, is a function that associates …