how i determine a face of a planar graph is convex polygon or not..............
closed as not a real question by Robin Chapman, Andrew Stacey, François G. Dorais♦, S. Carnahan♦, Pete L. Clark Jun 15 '10 at 15:12
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this is not a well defined question. Perhaps you mean that you want to know if a face of a planar embedding of a planar graph is convex ? Note that it's always possible to draw a planar graph so all faces (with the exception of the outer face) are convex