PROBLEM OF THE MONTH

March 2007




Congratulations to Gabriel Read, Say Cheong and Roman Kogan, this month's winners! Here is the solution by Say Cheong: [pdf]

A county has n > 4 cities. Prove that it is possible to connect some pairs of cities by one-way roads so that one can travel from every city to every other city using only one or two roads. Note that for every pair of cities A and B, only one road connecting A with B is allowed; this road leads from A to B or from B to A, but not both ways.

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 1st at 12 pm.