In the mathematical branch of graph theory, a graph is a structured collection of objects that represents the relationships between pairs of these objects. The objects appear as vertices (or nodes) in the graph, while the relation between a pair of objects is represented using an edge. A common way of illustrating a graph is by drawing the vertices as circles and the edges as connecting lines, as depicted in the following diagram of the Petersen graph, named after the Danish mathematician Julius Petersen:
Petersen graph
Source: https://commons.wikimedia.org/wiki/File:Petersen1_tiny.svg
Image by Leshabirukov. Licensed under Creative Commons CC BY-SA 3.0: https://creativecommons.org/licenses/by-sa/3.0/deed.en
Source: https://commons.wikimedia.org/wiki/File:Petersen1_tiny.svg
Image by Leshabirukov. Licensed under Creative Commons CC BY-SA 3.0: https://creativecommons.org/licenses/by-sa/3.0/deed.en
Graphs are remarkably useful objects as they can represent and help us research an overwhelming variety of real-life structures, patterns...