Skip to content

How a Simple Puzzle Revolutionized Mathematics

In Simple Terms

In the 1930s, a group of bright students in Budapest discussed a simple math puzzle. The puzzle asked if you could always make a four-sided shape from five random points on a paper. The answer was yes, leading to big discoveries in math and the development of Ramsey Theory, which explores finding order in chaos.

A Simple Challenge

In the early 1930s, a group of brilliant university students gathered in Budapest to discuss mathematical problems. Among them was the genius Paul Erdős, who would become one of the most prolific mathematicians in history, along with George Szekeres and Esther Klein. One day, Klein posed a puzzle to her colleagues: If you place five points on a paper such that no three are in a straight line, can you always form a convex quadrilateral with four of them?

The Simple Puzzle

The puzzle Klein presented seemed simple but was puzzling. The idea was to place five random points on a paper, ensuring that no three points were in a straight line, and determine if a convex quadrilateral could always be formed from four of them. The surprising answer was yes; such a shape could always be created, regardless of the point distribution.

To prove this, imagine the points as pegs sticking out of the paper. If you wrap a rubber band around these pegs, it will shrink around the outer points, forming a convex boundary. If the band covers four points with one inside, those four points indeed form a convex quadrilateral.

Impact on Mathematics

After presenting this puzzle, George Szekeres and Paul Erdős expanded on the idea in 1935. Their research showed that regardless of the number of sides needed, a finite number of points is sufficient to guarantee the formation of a convex polygon. This discovery laid the foundation for a mathematical theory now known as Ramsey Theory, which examines how order can emerge from chaos.

Ramsey Theory suggests that even within large, random systems, organized patterns inevitably appear. This theory remains a crucial focus in mathematical research today, posing the question of how large a system must be to ensure the emergence of order.

Love and Mathematics

Interestingly, this mathematical story has a romantic side. During discussions about the geometric puzzle, a love blossomed between Klein and Szekeres, leading to their marriage in 1937. Their relationship motivated them to continue contributing to mathematics, even after fleeing to Australia to escape Nazi persecution in Europe.

Conclusion

The five-point puzzle marked the beginning of a new chapter in mathematics history, contributing to the development of Ramsey Theory, which studies order within chaos. The love story between Klein and Szekeres adds a human dimension, reminding us that great discoveries can sometimes come from unexpected sources.