Seminars usually take place either at
UPV/EHU, Seminar Room of the Mathematics Department, Facultad de Ciencias, on Thursdays at 12:00, or
BCAM, Seminar Room, on Thursdays at 17:00.
Some seminars were recorded, and the videos can be found together with the description of the seminar on the subpage related to the year the talk happened. You can also find them here.
To subscribe to the seminar mailing list, contact one of the organizers.
As of December 18th, 2025, the count of talks reached 276.
BCAM, Thursday, January 8th, 2026, 17:00--18:00
Title: Maximal averages over hypersurfaces
Sewook Oh - KIAS, South Korea
Stein's spherical maximal function can be generalized to maximal averages over general hypersurfaces. Although this topic has been extensively studied, many problems still remain open.
In this talk, I will present Lp estimates for maximal averages associated to hypersurfaces, with particular emphasis on their relationship to the decay rate of the Fourier transform of measures supported on the hypersurfaces.
BCAM, Tuesday, January 13th, 2026, 17:00--18:00
Title: Estimates for oscillatory integrals with damping factors
Sanghyuk Lee - Seoul National University
Let $\sigma$ be the surface measure on a smooth hypersurface $\mathcal H \subset \mathbb{R}^{d+1}$. A fundamental subject in harmonic analysis is to determine the decay of $\widehat{\sigma}$. For nondegenerate $\mathcal H$, the stationary phase method yields the optimal decay, while sharp bounds in the degenerate case are known only in limited situations. In this talk, we are concerned with the oscillatory estimate
$$
|(\kappa^{1/2}\sigma)^\wedge(\xi)| \le C|\xi|^{-d/2},
$$
for convex analytic surfaces $\mathcal H$, where $\kappa$ is the Gaussian curvature. The damping factor $\kappa^{1/2}$ is expected to recover the optimal decay, as suggested by the stationary phase expansion, but the work of Cowling–Disney–Mauceri–Müller shows that such bounds fail in general for $d \ge 5$ even when the surface is convex and analytic. However, it has remained open whether the estimate holds in lower dimensions $2\le d\le 4$. We establish it for $d=2,3$, and with a logarithmic loss for $d=4$. Our approach is inspired by the stationary set method of Basu–Guo–Zhang–Zorin-Kranich. We also discuss applications to convolution, maximal, and adjoint restriction operators. This talk is based on joint work with Sewook Oh.
TBA, Thursday, January 15th, 2026, TBD
Title: TBA
André Laín Sanclemente - ICMAT
TBA
TBA, Thursday, January 22nd, 2026, TBD
Title: TBA
Claudia Peña Vázquez - BCAM
TBA
TBA, Thursday, January 29th, 2026, TBD
Title: TBA
Anxo Biasi
TBA