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#graphtheory

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The new algorithm for directed cheapest routes "slices the graph into layers, moving outward from the source like Dijkstra’s. But rather than deal with the whole frontier at each step, it uses the Bellman-Ford algorithm to pinpoint influential nodes, moves forward from these nodes to find the shortest paths to others, and later comes back to other frontier nodes. It doesn’t always find the nodes within each layer in order of increasing distance, so the sorting barrier doesn’t apply. And if you chop up the graph in the right way, it runs slightly faster than the best version of Dijkstra’s algorithm. It’s considerably more intricate, relying on many pieces that need to fit together just right. But curiously, none of the pieces use fancy mathematics."

quantamagazine.org/new-method-

A still from a video of nodes being connected by a white line
Quanta Magazine · New Method Is the Fastest Way To Find the Best Routes | Quanta MagazineA canonical problem in computer science is to find the shortest route to every point in a network. A new approach beats the classic algorithm taught in textbooks.

In our last #ISE2025 lecture last week, we were discussing what makes a node "important" in a knowledge graph. A simple heuristics can be borrowed from graph theory or communication theory: Degree Centrality

Interestingly, in Wikidata In-degree centrality states Jane Austen to be to most "important" female author, while Out-degree centrality claims J.K. Rowling as being more "important" ;-)

#knowledgegraphs #semanticweb #graphtheory #feminism #eyeofthebeholder @sourisnumerique @enorouzi

If I did everything right, I have a public alpha release of my graph (nodes and edges) editor
With source and windows binary !
(I hope)
It's a rolling chassis, to explore the design patterns for the ultimate goal of a #higraph editor.

#Python #PySide6 #graphTheory

github.com/ghillebrand/qtPyGra

GitHubGitHub - ghillebrand/qtPyGraphEdit at v0.0.0-alphaA graphical node-edge graph editor, in Python and Qt (PySide6) - GitHub - ghillebrand/qtPyGraphEdit at v0.0.0-alpha

A century-old enigma, graph theory and design
Behind a static form, there are connections, transformations and, above all, the elegance of mathematics.

👉 Discover MORE and SUBSCRIBE to our summary of news and updates through link: amusementlogic.com/general-new

📐 #graphtheory #mathematicaldesign #geometry #science #designscience #topology #computationaldesign #teoriadegrafos #diseñomatematico #geometria #ciencia #topologia #diseñocomputacional #sabiasque #saviezvousque #théoriedesgraphes

Ok, someone more familiar with graph theory tell me how to compute a minimum weight perfect matching on a complete graph with even-number of vertices? Or at least point me to a resource?

It's all either left as an exercise to the reader, extremely complex algorithms (Blossom or something?), or weird libraries, where apparently if I use it on complex graphs it's not necessary, but they then point me to even more complex papers.

Thought I had it solved but now it's returning a matching that's too small.

#graphtheory #computerscience #academia

Calling all #igraph enthusiasts!

We've identified and fixed a bug in {ig.degree.betweenness} related to the cluster_edge_betweenness() function.

The issue stemmed from a grep() action used for subgraph identification.

A fix has been implemented, and an update has been pushed to CRAN—it will be available in the coming days.

In the meantime, you can reinstall from the main branch here: github.com/benyamindsmith/ig.d

GitHubGitHub - benyamindsmith/ig.degree.betweenness: Smith-Pittman Community Detection Algorithm for 'igraph' Objects with RSmith-Pittman Community Detection Algorithm for 'igraph' Objects with R - benyamindsmith/ig.degree.betweenness

A question for the (combinatorial) hive mind.

There are a lot of extremal results that are matched asymptotically by some probabilistic construction, but with some gap, often quite substantial. I'm thinking about the Ramsey numbers R(k,k) or R(3,k), but examples of this phenomenon are prevalent.

I'm curious, does someone out there know of good examples of (extremal) results where some probabilistic construction (e.g. via a random graph) is matched asymptotically, and very precisely?

Efficiently Creating and Visualizing Symmetric Adjacency Matrices in Python
Master Python Adjacency Matrix techniques! Learn efficient creation, NetworkX visualization, & handling of large datasets. Represent & analyze complex relationships in your data. #PythonAdjacencyMatrix #GraphTheory #NetworkX #DataVisualization #DataScience #GraphAlgorithms
tech-champion.com/programming/

Network Graph Visualization: Improving Clarity in Dense Clusters with NetworkX
Improve Network Graph Visualization with NetworkX & Matplotlib! Learn simple yet effective strategies to enhance clarity, especially in dense clusters. Explore alternative layout algorithms & parameter adjustments for insightful data representation. #NetworkGraphVisualization #NetworkX #Matplotlib #DataVisualization #GraphTheory #Python
tech-champion.com/programming/

A post of @11011110 has reminded me that (after a year and a half lurking here) it's never too late for me to toot and pin an intro here.

I am a Canadian mathematician in the Netherlands, and I have been based at the University of Amsterdam since 2022. I also have some rich and longstanding ties to the UK, France, and Japan.

My interests are somewhere in the nexus of Combinatorics, Probability, and Algorithms. Specifically, I like graph colouring, random graphs, and probabilistic/extremal combinatorics. I have an appreciation for randomised algorithms, graph structure theory, and discrete geometry.

Around 2020, I began taking a more active role in the community, especially in efforts towards improved fairness and openness in science. I am proud to be part of a team that founded the journal, Innovations in Graph Theory (igt.centre-mersenne.org/), that launched in 2023. (That is probably the main reason I joined mathstodon!) I have also been a coordinator since 2020 of the informal research network, A Sparse (Graphs) Coalition (sparse-graphs.mimuw.edu.pl/), devoted to online collaborative workshops. In 2024, I helped spearhead the MathOA Diamond Open Access Stimulus Fund (mathoa.org/diamond-open-access).

Until now, my posts have mostly been about scientific publishing and combinatorics.

#introduction
#openscience
#diamondopenaccess
#scientificpublishing
#openaccess
#RemoteConferences
#combinatorics
#graphtheory
#ExtremalCombinatorics
#probability

igt.centre-mersenne.orgInnovations in Graph Theory Innovations in Graph Theory