MathDB
Picking Representatives of Sets

Source: APMO 2014 Problem 2

March 28, 2014
induction

Problem Statement

Let S={1,2,,2014}S = \{1,2,\dots,2014\}. For each non-empty subset TST \subseteq S, one of its members is chosen as its representative. Find the number of ways to assign representatives to all non-empty subsets of SS so that if a subset DSD \subseteq S is a disjoint union of non-empty subsets A,B,CSA, B, C \subseteq S, then the representative of DD is also the representative of one of AA, BB, CC.
Warut Suksompong, Thailand