every real number can be written in 2019 other sums
Source: 2019-20 International Dürer Competition, Category E+,P3
August 19, 2020
algebrareal numberscountingExtremal combinatorics
Problem Statement
At least how many non-zero real numbers do we have to select such that every one of them can be written as a sum of other selected numbers and
a) the selected numbers are not necessarily different?
b) the selected numbers are pairwise different?