In collaboration with Payame Noor University and the Iranian Society of Instrumentation and Control Engineers
Optimization & Operations Research
A Metaheuristic and LP-Based Approach to Irregular Face Coloring in Planar Graphs

Maedeh Shahabi; Freydoon Rahbarnia

Volume 11, Issue 1 , January 2026, , Pages 141-151

https://doi.org/10.30473/coam.2025.75246.1325

Abstract
  In irregular coloring, each vertex is labeled with a unique color code, a tuple consisting of its assigned color and the number of neighbors in each color class‎. ‎This work proposes a local search algorithm as a metaheuristic approach to the irregular face coloring problem in planar graphs‎, ...  Read More

A Metaheuristic and LP-Based Approach to Irregular Face Coloring in Planar Graphs


The Smallest Number of Colors Needed for a‎ ‎Coloring of the Square of the Cartesian Product of Certain Graphs

Sajad Sohrabi Hesan; Freydoon Rahbarnia; Mostafa Tavakolli

Volume 8, Issue 1 , June 2023, , Pages 83-93

https://doi.org/10.30473/coam.2022.54855.1194

Abstract
  Given any graph G‎, ‎its square graph G^2 has the same vertex set as G, ‎with two vertices adjacent in G^2 whenever they are at distance 1 or 2 in G. ‎‎The Cartesian product of graphs G and H is denoted by G□ H. ‎‎One of the most studied NP-hard problems is the graph coloring ...  Read More