Problems/Erdos-Ginzburg-Ziv Theorem

Erdos-Ginzburg-Ziv Theorem

Number TheorySOLVED
Year
1961
Difficulty
*****
Solved by
Paul Erdos, Abraham Ginzburg & Abraham Ziv (1961)

Statement

Among any 2n-1 integers, there exist n whose sum is divisible by n.

∀ a1,…,a2n−1∈Z,  ∃ S⊂[2n−1],  ∣S∣=n:∑i∈Sai≡0(modn)\forall\, a_1,\ldots,a_{2n-1} \in \mathbb{Z},\; \exists\, S \subset [2n-1],\; |S|=n : \sum_{i\in S} a_i \equiv 0 \pmod{n}

About this Problem

Launched the field of zero-sum theory. The bound 2n-1 is tight.

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