tilings with m x n rectangles with corners
Source: JBMO Shortlist 2007 C1
October 14, 2017
JBMOcombinatorics
Problem Statement
We call a tiling of an rectangle with corners (see figure below) "regular" if there is no sub-rectangle which is tiled with corners. Prove that if for some and there exists a "regular" tiling of the rectangular then there exists a "regular" tiling also for the rectangle.