for G1 being _Graph
for G2 being Subgraph of G1
for v1 being Vertex of G1
for v2 being Vertex of G2 st v1 = v2 holds
( v2 .inNeighbors() c= v1 .inNeighbors() & v2 .outNeighbors() c= v1 .outNeighbors() & v2 .allNeighbors() c= v1 .allNeighbors() )