Problem

Source: IMO Shortlist 1993, United Kingdom 3

Tags: induction, number theory, Subsets, Additive Number Theory, IMO Shortlist, Divisibility



Show that for any finite set $S$ of distinct positive integers, we can find a set $T \supseteq S$ such that every member of $T$ divides the sum of all the members of $T$. Original Statement: A finite set of (distinct) positive integers is called a DS-set if each of the integers divides the sum of them all. Prove that every finite set of positive integers is a subset of some DS-set.