Wu, Jie On the primitive circle problem. (English) Zbl 0994.11035 Monatsh. Math. 135, No. 1, 69-81 (2002). Let \(V(x)\) be the number of primitive lattice points \((m,n)\) in the circle given by \(m^2+n^2\leq x\), where \((m,n)\) is said to be primitive if \(\text{h.c.f.}(m,n)=1\). Then it is shown, subject to the Riemann hypothesis, that \[ V(x)= \tfrac {6}{\pi}+ O(x^{221/608+ \varepsilon}) \] for any \(\varepsilon> 0\). Unconditionally the best exponent known is only \(1/2\). Previously the best known conditional exponent was \(11/30+ \varepsilon\), due to W. Zhai and X. Cao [Acta Arith. 90, 1-16 (1999; Zbl 0932.11066)]. Bounds for multidimensional exponential sums are the main ingredient of the proof. Reviewer: Roger Heath-Brown (Oxford) Cited in 1 ReviewCited in 14 Documents MSC: 11P21 Lattice points in specified regions 11L07 Estimates on exponential sums 11N37 Asymptotic results on arithmetic functions Keywords:circle problem; error term; bounds for multidimensional exponential sums; number of primitive lattice points; Riemann hypothesis Citations:Zbl 0932.11066 PDFBibTeX XMLCite \textit{J. Wu}, Monatsh. Math. 135, No. 1, 69--81 (2002; Zbl 0994.11035) Full Text: DOI