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Miklós Schweitzer
1996 Miklós Schweitzer
3
zero sum
zero sum
Source: miklos schweitzer 1996 q3
October 12, 2021
linear algebra
Problem Statement
Let
1
≤
a
1
<
a
2
<
.
.
.
<
a
2
n
≤
4
n
−
2
1\leq a_1 < a_2 <... < a_{2n} \leq 4n-2
1
≤
a
1
<
a
2
<
...
<
a
2
n
≤
4
n
−
2
be integers, such that their sum is even. Prove that for all sufficiently large n, there exist
ε
1
,
.
.
.
,
ε
2
n
=
±
1
\varepsilon_1 , ..., \varepsilon_{2n} = \pm1
ε
1
,
...
,
ε
2
n
=
±
1
such that
∑
ε
i
=
∑
ε
i
a
i
=
0
\sum\varepsilon_i = \sum\varepsilon_i a_i = 0
∑
ε
i
=
∑
ε
i
a
i
=
0
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