Balancing Polynomials in the Chebyshev Norm


Abstract in English

Given $n$ polynomials $p_1, dots, p_n$ of degree at most $n$ with $|p_i|_infty le 1$ for $i in [n]$, we show there exist signs $x_1, dots, x_n in {-1,1}$ so that [Big|sum_{i=1}^n x_i p_iBig|_infty < 30sqrt{n}, ] where $|p|_infty := sup_{|x| le 1} |p(x)|$. This result extends the Rudin-Shapiro sequence, which gives an upper bound of $O(sqrt{n})$ for the Chebyshev polynomials $T_1, dots, T_n$, and can be seen as a polynomial analogue of Spencers six standard deviations theorem.

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