Landesman's conjecture on resultant equation counts

Let n2n\geqslant 2 and let

Nn(B)=#{(a,b,c)Z3:a,b,cBRes(R,ax2+bx+c)=±1for some RZ[x] of degree n}.N_n(B)=\#\left\{(a,b,c)\in \mathbb{Z}^3: \begin{array}{l} |a|,|b|,|c|\leqslant B\\ \operatorname{Res}(R,ax^2+bx+c)=\pm 1\\ \text{for some $R\in \mathbb{Z}[x]$ of degree $n$} \end{array} \right\}.

Landesman's conjecture. There exists m0m\geqslant 0 such that

Nn(B)B2(logB)m.N_n(B)\ll B^{2}(\log B)^m.

The conjecture predicts that, for every fixed degree n2n\geqslant 2, the quadratic polynomials counted by the resultant equation have essentially quadratic growth, up to a power of logB\log B. The paper proves an upper bound of order B3/logBB^3/\sqrt{\log B} when the degree of RR is odd, while the conjectured bound remains open in general.

Sources & referencesView supporting material

Primary source

Tim Browning and Stephanie Chan, “Solubility of a resultant equation and applications”, arXiv:2411.09264 (2025).

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