PLANARITAS SUATU GRAF

Graph theory is one of math topic that even with its young age, has already been developed a lot. This essay will be focused on planar graph, which is a graph that can be drawn on a plane without any of the edges crossing. This essay intends to figure out the steps needed to know a graph’s planarity and the method used is literature study. After using Euler theorem and Kuratowski theorem along with the theorems that is related to them, it turns out that there are graphs that aren’t planar, which are graphs that include K_3,3 and K_5 as a subgraph, both as it is, as a result of subdivision, and as a result of contraction, are also not planar. One of them is Petersen graph. On the other hand, there are graphs that at a first glance don’t look planar but after investigating and redrawing them turn out to be planar, for example the second graph used in discussion