theorem Th60: :: GLIBPRE0:54

for G1 being _Graph
for E being set
for G2 being reverseEdgeDirections of G1,E
for v1 being Vertex of G1
for v2 being Vertex of G2 st v1 = v2 holds
( v2 .edgesInOut() = v1 .edgesInOut() & v2 .degree() = v1 .degree() )