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A Computer Proof of Turan's Inequality

S. Gerhold·M. Kauers
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Abstract

We show how Turan's inequality $P_n(x)^2-P_{n-1}(x)P_{n+1}(x)\geq 0$ for Legendre polynomials and related inequalities can be proven by means of a computer procedure. The use of this procedure simplifies the daily work with inequalities. For instance, we have found the stronger inequality $|x|P_n(x)^2-P_{n-1}(x)P_{n+1}(x)\geq 0$, $-1\leq x\leq 1$, effortlessly with the aid of our method.

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S. Gerhold, M. Kauers. 2005-09-21. A Computer Proof of Turan's Inequality. https://arxiv.org/abs/math/0509468

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