EN
It is shown that the operator below maps $L^{p}$ into itself for 1 < p < ∞.
$Cf(x) := sup_{a,b} |p.v. ∫ f(x-y)e^{i(ay²+by)} dy/y|$.
The supremum over b alone gives the famous theorem of L. Carleson [2] on the pointwise convergence of Fourier series. The supremum over a alone is an observation of E. M. Stein [12]. The method of proof builds upon Stein's observation and an approach to Carleson's theorem jointly developed by the author and C. M. Thiele [7].