MathDB

4

Part of 2006 Lithuania National Olympiad

Problems(1)

Maximal cardinality

Source: Lithuanian Mathematical Olympiad 2006

4/12/2006
Find the maximal cardinality ∣S∣|S| of the subset S⊂A={1,2,3,…,9}S \subset A=\{1, 2, 3, \dots, 9\} given that no two sums a+b∣a,b∈S,a≠ba+b | a, b \in S, a \neq b are equal.
combinatoricscombinatorics proposedcombinatorics solvedSetsSubsetscardinalityuniqueness