2001 USAMO Problems/Problem 5
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Problem
Let 
be a set of integers (not necessarily positive) such that
(a) there exist 
with 
;
(b) if 
and 
are elements of (possibly equal), then 
also belongs to .
Prove that is the set of all integers.
Solution
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See also
| 2001 USAMO (Problems • Resources: AoPS | ML) | ||
| Preceded by Problem 4 | 1 • 2 • 3 • 4 • 5 • 6 | Followed by Problem 6 |
