Fullerenes 1

Planar Graph
A graph is planar planar if it can be drawn in the plane without crossings.
Its regions are called faces, faces,
ff. . The unbounded region is called
the exterior exterior face (Harary ( Harary). ). 1
A graph is planar if and only if it has no subgraphs homeomorphic
homeomorphic
to
(Kuratowski). 2
to KK 55 or KK 3,3 3,3 (Kuratowski).
f 1
f 2
f 3 f 4
1. Harary , F. Graph Theory, Theory,
Addison - Wesley, Reading, M.A., 1969.
2. Kuratowski, K. Sur la Problème des Courbes Gauches en Topologie,
Topologie,
Fund. Math. Math.
1930, 15, 15,
271-283. 271 283.
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