graph theory:
    other name: isomorphism of graphs
    
    Let G=(`V_1`, `E_1`) and H=(`V_2`, `E_2`) be two graphs. We call G and H isomorphic graphs (denoted G`~=`H), if there exists a bijection $varphi : V_1 rightarrow V_2$ with uv $in E_1 Leftrightarrow varphi(u)varphi(v) in E_2$ for all u,v`in V_1`.
    
    Map `varphi` is called isomorphism.
    
    Example of isomorphic graphs:
    
    
    A graph map `G->H` is called an isomorphism of graphs, if vertex function `V_G->V_H` and edge function `E_G->E_H` are one-to-one functions and onto functions.