MathDB

Problem 2

Part of 1996 Yugoslav Team Selection Test

Problems(1)

1996 circles in plane, circle touching three others

Source: Yugoslav TST 1996 P2

5/16/2021
Let there be given a set of 19961996 equal circles in the plane, no two of them having common interior points. Prove that there exists a circle touching at most three other circles.
geometrycombinatoricscombinatorial geometry