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1 rectangle intersects all rectangles - All-Russian MO 2002 Regional (R4) 9.4

Source:

September 17, 2024
combinatoricscombinatorial geometryrectanglegeometry

Problem Statement

Located on the plane [43n]\left[ \frac43 n \right] rectangles with sides parallel to the coordinate axes. It is known that any rectangle intersects at least n rectangles. Prove that exists a rectangle that intersects all rectangles.