for G1, G2 being _Graph
for X, Y being set st G1 == G2 holds
( G1 .order() = G2 .order() & G1 .size() = G2 .size() & G1 .edgesInto X = G2 .edgesInto X & G1 .edgesOutOf X = G2 .edgesOutOf X & G1 .edgesInOut X = G2 .edgesInOut X & G1 .edgesBetween X = G2 .edgesBetween X & G1 .edgesDBetween (X,Y) = G2 .edgesDBetween (X,Y) )