Mathematical and Physical Journal
for High Schools
Issued by the MATFUND Foundation
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Problem A. 601. (November 2013)

A. 601. Let q\ge1 be an integer. Prove that there is an integer Cq such that for every finite set A of integers |A+q.A|\ge(q+1)|A|-Cq holds. (A+q.A is the set of those integers that can be expressed as a+qa' with some a,a'\inA.)

Schweitzer competition, 2013

(5 pont)

Deadline expired on December 10, 2013.

Sorry, the solution is available only in Hungarian. Google translation

A megoldás megtalálható a Schweitzer-verseny honlapján.


2 students sent a solution.
0 point:2 students.

Problems in Mathematics of KöMaL, November 2013