Johnny Lim

collaborators

Showing math.COShow all

6 papers · 1 filter

math.CO2026

Steinerberger Curvature On Digraphs -- Discrete Bonnet-Myers and Lichnerowicz Theorems

Kevin Fung, Johnny Lim

Steinerberger curvature encodes the global distance geometry of a graph through an equilibrium measure. In this paper, we derive explicit curvature formulas for undirected Cayley g…

math.CO2026

Lin--Lu--Yau Ricci Curvature of Digraphs via Optimal Transport Couplings

Kevin Fung, Johnny Lim

In this paper, we study the Lin--Lu--Yau Ricci curvature of strongly connected locally finite digraphs through an explicit optimal-coupling construction. For an arc of a digraph, w…

math.CO2025

A Characterization of Triangle-Free Cyclic Graphs With Self-Loops Of Rank 3

Johnny Lim

Let $G_{S}$ be a self-loop graph as the graph obtained by attaching a self-loop at every vertex in $S \subseteq V (G)$ of a simple graph $G .$ If $G = C_{n}$ is the cycle graphs of order $…

math.CO2025

Closed Walks Of Low Dimension And Twisted Moments On Self-Loop Graphs

Johnny Lim

Let $G_{S}$ be a graph with loops attached at each vertex in $S \subseteq V (G) .$ In this article, we develop exact formulae for the number of closed $3$ - and $4$ -walks on $G_{S}$ in te…

math.CO2025

On the spectrum and energy of digraphs with self-loops

Kevin Fung, Johnny Lim

A digraph with self-loops $D_{S}$ with vertex set $V$ is a simple digraph with a self-loop attached at every vertex in $S \subset V .$ In this paper, we study the…

math.CO2024

Line graphs and Nordhaus-Gaddum-type bounds for self-loop graphs

Saieed Akbari, Irena M. JovanoviÄ, Johnny Lim

Let $G_{S}$ be the graph obtained by attaching a self-loop at every vertex in $S \subseteq V (G)$ of a simple graph $G$ of order $n .$ In this paper, we explore several new results rel…