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arXiv · 2609.22330

A Proof of the Common Root Conjecture for Legendre Polynomials

Zikang Deng
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Abstract

We prove Stieltjes' common root conjecture: Legendre polynomials of distinct degrees have no common nonzero root. We construct an auxiliary polynomial and show that, for the relevant power of two $q\ge2$, the edge of slope $1/q$ in its $2$-adic Newton polygon has horizontal length less than $3q$. If a common nonzero root existed, Newton polygon theory and the Legendre differential equation would force the same edge to have horizontal length at least $3q$, yielding a contradiction.

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Zikang Deng. 2026-09-16. A Proof of the Common Root Conjecture for Legendre Polynomials. https://arxiv.org/abs/2609.22330

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