MathDB

271

Part of 1979 All Soviet Union Mathematical Olympiad

Problems(1)

ASU 271 All Soviet Union MO 1979 enemies of members of parliament

Source:

7/14/2019
Every member of a certain parliament has not more than 33 enemies. Prove that it is possible to divide it onto two subparliaments so, that everyone will have not more than one enemy in his subparliament. (AA is the enemy of BB if and only if BB is the enemy of AA.)
combinatorics