MathDB
reflection of vertices wrt diagonal not outside polygon

Source: JBMO 2011 Shortlist C8

October 14, 2017
reflectionJBMOcombinatoricscombinatorial geometry

Problem Statement

Determine the polygons with nn sides (n4)(n \ge 4), not necessarily convex, which satisfy the property that the reflection of every vertex of polygon with respect to every diagonal of the polygon does not fall outside the polygon. Note: Each segment joining two non-neighboring vertices of the polygon is a diagonal. The reflection is considered with respect to the support line of the diagonal.