MathDB

1

Part of 2005 Austrian-Polish Competition

Problems(1)

Number of diagonal-quadrangles

Source: Austrian-Polish 2005, Problem 1

7/5/2015
For a convex nn-gon PnP_n, we say that a convex quadrangle QQ is a diagonal-quadrangle of PnP_n, if its vertices are vertices of PnP_n and its sides are diagonals of PnP_n. Let dnd_n be the number of diagonal-quadrangles of a convex nn-gon. Determine dnd_n for all n≥8n\geq 8.
EnumerationcombinatoricsPolygons