Consider any two [[Graphs|graphs]] $G_{1}=(V,E)$ and $G_{2}=(W,F)$. $G_{1}$ and $G_{2}$ are isomorphic iff there is a [[Bijection|bijection]] $f:V\to W$ such that $(v_{1},v_{2})\in E \iff\left(f(v_{1}),\, f(v_{2})\right)\in F$. The bijection $f$ is called an [[Isomorphism|isomorphism]]. We write $G_{1}\cong G_{2}$. # Bibliography 1. https://en.wikipedia.org/wiki/Graph_isomorphism_problem