PROBLEM OF THE MONTH

March 2006





Congratulations to this month winners Say Cheong, Itamar Gal, Clayton Bailey-Assam and Amghibech Said!
Solution by Itamar Gal: [pdf]


There are three colleges in a town. Each college has n students. Any student of any college knows n+1 students of the other two colleges. Prove that it is possible to choose a student from each of the three colleges so that all three students would know each other.
Hint: solve this problem for small n first (take n=2,3,4).

This month's prize will be awarded to the best explained, correct solution.



Submit your solution to the Mathematics Undergraduate Office (Math P-142) or electronically to problem@math.sunysb.edu by the due date. Acceptable electronic formats are: PDF, Postscript, DVI, (La)TeX, or just plain text. Please include your name and phone number, or preferably your email address.

Closing date: April 10th at 12 pm.