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João P. G. Ramos

Publications and source records attributed to João P. G. Ramos.

39 records · Page 3Linked to original sources

Fourier uniqueness pairs of powers of integers

We prove, under certain conditions on $(α,β)$, that each Schwartz function $f$ such that $f(\pm n^α) = \hat{f}(\pm n^β) = 0, \forall n \ge 0$ must vanish identically, complementing a series of recent results involving uncertainty principles, such as the pointwise interpolation formulas by Radchenko and Viazovska and the Meyer-Guinnand construction of self-dual crystaline measures.

math.CA↗

The Hilbert transform along the parabola, the polynomial Carleson theorem and oscillatory singular integrals

We make progress on an interesting problem on the boundedness of maximal modulations of the Hilbert transform along the parabola. Namely, if we consider the multiplier arising from it and restrict it to lines, we prove uniform $L^p$ bounds for maximal modulations of the associated operators. Our methods consist of identifying where to use effectively the polynomial Carleson theorem, and where we can take advantage of the presence of oscillation to obtain decay through the $TT^*$ method.

math.CA↗

Maximal restriction estimates and the maximal function of the Fourier transform

We prove a maximal restriction inequality for the Fourier transform, providing an answer to a question left open by Müller, Ricci and Wright. Our methods are similar to the ones in their article, with the addition of a suitable trick to help us linearise our maximal function. In the end, we comment on how to use the same trick in combination with Vitturi's approach to obtain a stronger high-dimensional result.

math.CA↗