for G1, G2 being _Graph
for F being PGraphMapping of G1,G2 st F is isomorphism holds
( ( G1 is vertex-finite implies G2 is vertex-finite ) & ( G2 is vertex-finite implies G1 is vertex-finite ) & ( G1 is edge-finite implies G2 is edge-finite ) & ( G2 is edge-finite implies G1 is edge-finite ) ) by Th13, Th14;