2017/02/07 by Birklbauer, Philipp, Iosevich, Alex
#Classical Analysis and ODEs (math.CA) #Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.1702.02126
We study the following two-parameter variant of the Erd\H os-Falconer distance problem. Given E,F ⊂ \Bbb Fqk+l, l ≥ k ≥ 2, the k+l-dimensional vector space over the finite field with q elements, let Bk,l(E,F) be given by \(\Vert x'-y'\Vert, \Vert x"-y" \Vert): x=(x',x") ∈ E, y=(y',y") ∈ F; x',y' ∈ \Bbb Fqk, x",y" ∈ \Bbb Fql \. We prove that if |E||F| ≥ C qk+2l+1, then Bk,l(E,F)=\Bbb Fq × \Bbb Fq. Furthermore this result is sharp if k is odd. For the case of l=k=2 and q a prime with q ≡ 3 \mod 4 we get that for every positive C there is c such that if |E||F|gt;C q6+(2)/(3), then |B2,2(E,F)|gt; c q2.