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1987 Austrian-Polish Competition
4
problem from Austrian - Polish Math Competition
problem from Austrian - Polish Math Competition
Source:
December 17, 2010
combinatorics unsolved
combinatorics
Problem Statement
Does the set
{
1
,
2
,
3
,
.
.
.
,
3000
}
\{1,2,3,...,3000\}
{
1
,
2
,
3
,
...
,
3000
}
contain a subset
A
A
A
consisting of 2000 numbers that
x
∈
A
x\in A
x
∈
A
implies
2
x
∉
A
2x \notin A
2
x
∈
/
A
?!! :?:
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