Which one of the following graphs is NOT planar?
why is g1 not planar? We can create planar structure of G1 also
You Number them first and then make planar(G1)
you can not make the planar graph
A finite graph is planar if and only if it does not contain a subgraph that is a subdivision of the complete graph K5 or the complete bipartite graph K3,3 (utility graph). Source
G1 is exactly K3,3 but drawn in a different way. See this
We can form a planar graph for all except G1. Hence G1 is not planar graph.
if G1 is non-planar, then it shouldn't satisfy 3v-e>=6 this inequality right ?
but it does
3*6-9>=6 --> 9>=6 (Satisfied)
It is necessary condition to be planar not sufficient.