MathDB

A6

Part of 1973 Putnam

Problems(1)

Putnam 1973 A6

Source: Putnam 1973

5/25/2022
Prove that it is impossible for seven distinct straight lines to be situated in the euclidean plane so as to have at least six points where exactly three of these lines intersect and at least four points where exactly two of these lines intersect.
Putnamgeometrylines