My research concerns problems from Harmonic Analysis and Partial Differential Equations.
Publications
(Note that some papers can have an appearance and a format different to the used in the corresponding journal. Also, perhaps the final version in the journal will have some other minor changes)Preprints
J. Lee, S. Lee, L. Roncal, Strichartz and local smoothing estimates for the fractional Schrödinger equations over fractal time, arXiv:2508.16102
S. Lee, L. Roncal, F. Zhang, S. Zhao, Endpoint estimates for the fractal circular maximal function and related local smoothing, arXiv:2506.20390
D. Mena, M. C. Reguera, L. Roncal, Weighted weak type estimates for non-integral square functions, arXiv:2506.14897
M. Fraccaroli, D. Kosz, L. Roncal, On differentiation of integrals in Lebesgue spaces, arXiv:2505.05425
A. Fernández-Bertolin, L. Roncal, D. Stan, Landis-type results for discrete equations, arXiv: 2401.09066
Published (or accepted for publication)
L. Fanelli, H. Mizutani, L. Roncal, Nico M. Schiavone, Uniform resolvent estimates, smoothing effects and spectral stability for the Heisenberg sublaplacian, arXiv: 2409.11943, to appear in J. Anal. Math.
F. Di Plinio, M. Flórez-Amatriain, I. Parissis, L. Roncal, Pointwise localization and sharp weighted bounds for Rubio de Francia square functions, Publ. Mat. 69 (2025), no. 2, 445-471.
L. Fanelli, H. Mizutani, L. Roncal, Nico M. Schiavone, Non-existence of radial eigenfunctions for the perturbed Heisenberg sublaplacian, J. Fourier Anal. Appl. 31 (2025), Paper No. 37.
H. Gimperlein, B. Krötz, L. Roncal, S. Thangavelu, Poisson transform and unipotent complex geometry, J. Funct. Anal. 288 (2025), no. 3, Paper No. 110742.
O. Bakas, F. Di Plinio, I. Parissis, and L. Roncal, Singular integrals along variable codimension one subspaces, Ars Inven. Anal. 2024, Paper No. 2, 53 pp.
A. Fernández-Bertolin, L. Roncal, A. Rüland, On (global) unique continuation properties of the fractional discrete Laplacian, J. Funct. Anal. 286 (2024), no. 9, Paper No. 110375.
N. Accomazzo, F. Di Plinio, P. Hagelstein, I. Parissis, L. Roncal, Directional square functions, Anal. PDE. 16 (2023), 1651-1699.
A. Nowak, L. Roncal, T.Z. Szarek, Endpoint estimates and optimality for the generalized spherical maximal operator on radial functions, Comm. Pure Appl. Anal. 22 (2023), 2233-2277.
D. Kosz, G. Rey, L. Roncal, Weak-type maximal function estimates on the infinite-dimensional torus, Math. Z. 304 (2023), 43.
L. Fanelli, L. Roncal, Kato-Ponce estimates for fractional sublaplacians in the Heisenberg group, Bull. Lond. Math. Soc. 55 (2023), 611-639.
D. Kosz, J. Martínez-Perales, V. Paternostro, E. Rela, L. Roncal, Maximal operators on the infinite-dimensional torus, Math. Annalen 385 (2023), 1-39.
L. Roncal, D. Stan, L. Vega, Carleman type inequalities for fractional relativistic operators, Rev. Mat. Complut. 36 (2023), 301-332.
L. Roncal and S. Thangavelu, Corregindum to: An extension problem and trace Hardy inequality for the sublaplacian on $H$-type groups, Int. Math. Res. Not. IMRN 12 (2022), 9598-9602.
D. Beltran, R. Oberlin, L. Roncal, A. Seeger, B. Stovall, Variation bounds for spherical averages, Math. Annalen 382 (2022), no. 1-2, 459-512.
L. Roncal, Hardy type inequalities for the fractional relativistic operator, Math. Eng. 4 (2022), no. 3, Paper No. 18, 16pp.
J. Canto, K. Li, L. Roncal, O. Tapiola, $C_p$ estimates for rough homogeneous singular integrals and sparse forms, Ann. Sc. Norm. Super. Pisa Cl. Sci. (5) 22 (2021), no.3, 1131-1168.
A. Fernández-Bertolin, L. Roncal, A. Rüland, D. Stan, Discrete Carleman estimates and three balls inequalities, Calc. Var. Partial Differential Equations 60 (2021), no.6, Paper No. 239.
L. Roncal, S. Shrivastava, K. Shuin, Bilinear spherical maximal functions of product type, J. Fourier Anal. Appl. 27 (2021), Paper No. 73.
S. Bagchi, S. Hait, L. Roncal, S. Thangavelu, On the maximal function associated to the spherical means on the Heisenberg group, New York J. Math. 27 (2021), 631-675.
R. Garg, L. Roncal, S. Shrivastava, Quantitative weighted estimates for Rubio de Francia's Littlewood--Paley square function, J. Geom. Anal. 31 (2021), 748-771.
E. Fernández, L. Roncal, A decomposition of Calderón-Zygmund type and some observations on differentiation of integrals on the infinite-dimensional torus, Potential Anal. 53 (2020), 1449-1465.
L. Roncal, S. Thangavelu, An extension problem and trace Hardy inequality for the sublaplacian on $H$-type groups, Int. Math. Res. Not. IMRN 14 (2020), 4238-4294.
Ó. Ciaurri, A. Nowak, L. Roncal, Maximal estimates for a generalized spherical mean Radon transform acting on radial functions, Ann. Mat. Pura Appl. (4) 199 (2020), 1597-1619.
P. Boggarapu, L. Roncal, S. Thangavelu, On extension problem, trace Hardy and Hardy's inequalities for some fractional Laplacians, Comm. Pure Appl. Anal. 18 (2019), 2575-2605.
K. Li, C. Pérez, I.P. Rivera-Ríos, L. Roncal, Weighted norm inequalities for rough singular integral operators, J. Geom. Anal. 29 (2019), 2526-2564
E. Fernández, L. Roncal, On the absolute divergence of Fourier series in the infinite dimensional torus, Colloq. Math. 157 (2019), 143-155
C. Pérez, I.P. Rivera-Ríos, L. Roncal, $A_1$ theory of weights for rough homogeneous singular integrals and commutators, Ann. Sc. Norm. Super. Pisa Cl. Sci. (5) 19 (2019), 169-190
Ó. Ciaurri, L. Roncal, S. Thangavelu, Hardy-type inequalities for fractional powers of the Dunkl--Hermite operator, Proc. Edinburgh Math. Soc. (2) 61 (2018), no. 2, 513–544
Ó. Ciaurri, L. Roncal, P. R. Stinga, J.L. Torrea, J.L. Varona, Nonlocal discrete diffusion equations and the fractional discrete Laplacian, regularity and applications, Adv. Math. 330 (2018), 688-738
C. Lizama, L. Roncal, Hölder-Lebesgue regularity and almost periodicity for semidiscrete equations with a fractional Laplacian, Discrete Contin. Dyn. Syst. 38 (2018), no.3, 1365-1403
Ó. Ciaurri, L. Roncal, Vector-valued extensions for fractional integrals of Laguerre expansions, Studia Math. 240 (2018), no.1, 69-99
Ó. Ciaurri, A. Nowak, L. Roncal, Two-weight mixed norm estimates for generalized spherical mean Radon transform acting on radial functions, SIAM J. Math. Anal. 49 (2017), no. 6, 4402-4439
P. Boggarapu, L. Roncal, S. Thangavelu, Mixed norm estimates for the Cesàro means associated with Dunkl--Hermite expansions, Trans. Amer. Math. Soc. 369 (2017), 7021-7047
Ó. Ciaurri, T. A. Gillespie, L. Roncal, J. L. Torrea, J. L. Varona, Harmonic Analysis associated with a discrete Laplacian, J. Anal. Math. 132 (2017), 109-131
T. P. Hytönen, L. Roncal, O. Tapiola, Quantitative weighted estimates for rough homogeneous singular integrals, Israel J. Math. 218 (2017), 133--164
Ó. Ciaurri, E. Fernández, L. Roncal, Revisiting floating bodies, Expo. Math. 34 (2016), 396-422
L. Roncal, S. Thangavelu, Hardy's inequality for fractional powers of the sublaplacian on the Heisenberg group, Adv. Math. 302 (2016), 106-158
J. Dziubanski, M. Preisner, L. Roncal, P. R. Stinga, Hardy spaces for Fourier-Bessel expansions, J. Anal. Math. 128 (2016), 261-287
L. Roncal, P. R. Stinga, Fractional Laplacian on the torus, Commun. Contemp. Math. 18 (2016) 1550033, 26 pp.
Ó. Ciaurri, L. Roncal, P. R. Stinga, Riesz transforms on compact Riemannian symmetric spaces of rank one, Milan J. Math. 83 (2015), 345-370
Ó. Ciaurri, C. Lizama, L. Roncal, J. L. Varona, On a connection between the discrete fractional Laplacian and superdiffusion, Appl. Math. Lett. 49 (2015), 119-125
Ó. Ciaurri, L. Roncal, J. L. Varona, The multiplier of the interval $[-1,1]$ for the Dunkl transform of arbitrary order on the real line, Integral Transforms Spec. Funct. 26 (2015), 728-736
A. Nowak, L. Roncal, Potential operators associated with Jacobi and Fourier-Bessel expansions, J. Math. Anal. Appl. 422 (2015), 148-184
Ó. Ciaurri, L. Roncal, The Riesz transform for the harmonic oscillator in spherical coordinates, Constr. Approx. 40 (2014), 447-472
A. Nowak and L. Roncal, On sharp heat and subordinated kernel estimates in the Fourier-Bessel setting, Rocky Mountain J. Math. 44 (2014), 1321-1342
A. Nowak, L. Roncal, Sharp heat kernel estimates in the Fourier-Bessel setting for a continuous range of the type parameter, Acta Math. Sin. 30 (2014), 437-444
Ó. Ciaurri, L. Roncal, The wave equation for the Bessel Laplacian, J. Math. Anal. Appl. 409 (2014), 263-274
Ó. Ciaurri, L. Roncal, P. R. Stinga, Fractional integrals on compact Riemannian symmetric spaces of rank one, Adv. Math. 235 (2013), 627-647
Ó. Ciaurri, L. Roncal, Bochner-Riesz means for Fourier-Bessel expansions: norm inequalities for the maximal operator and almost everywhere convergence, J. Approx. Theory 167 (2013), 121-146
Ó. Ciaurri, L. Roncal, Higher order Riesz transforms for Fourier-Bessel expansions, J. Fourier Anal. Appl. 18 (2012), 770-789
A. Nowak, L. Roncal, K. Stempak, Riesz transforms for the Dunkl Ornstein-Uhlenbeck semigroup, Colloq. Math. 118 (2010), 669-684
V. Kolyada, L. Roncal, Jacobi transplantations and Weyl integrals, Collect. Math. 61 (2010), 205-221
Ó. Ciaurri, L. Roncal, Littlewood-Paley-Stein $g_k$-functions for Fourier-Bessel expansions, J. Funct. Anal. 258 (2010), 2173-2204
Ó. Ciaurri, L. Roncal, Weighted inequalities for the Bochner-Riesz means related to the Fourier-Bessel expansions, J. Math. Anal. Appl. 329 (2007), 1170-1180
Ó. Ciaurri, L. Roncal, The Bochner-Riesz means for Fourier-Bessel expansions, J. Funct. Anal. 228 (2005), 89-113
Conference proceedings, book chapters, survey articles
A. Fernández-Bertolin, L. Roncal, D. Stan, Landis' conjecture: a survey, arXiv:2412.00788, to appear in Harmonic Analysis and Nonlinear Partial Differential Equations, RIMS Kôkyûroku Bessatsu, 2025
S. Kumar, F. Ponce-Vanegas, L. Roncal, L. Vega, The Frisch-Parisi formalism for fluctuations of the Schrödinger equation, Mathematical Physics and Its Interactions, 199–223, Springer Proc. Math. Stat., 451, Springer, Singapore, 2024
L. Roncal, Huellas del análisis de Fourier en el Premio Princesa de Asturias de Investigación Científica y Técnica 2020, Gac. R. Soc. Mat. Esp. 24 (2021), 35-54
Ó. Ciaurri, L. Roncal, Hardy's inequality for the fractional powers of a discrete Laplacian, J. Anal. 26 (2018), no. 2, 211-225, Proceedings of 20th Ramanujan Symposium International Conference
A. Arenas, Ó. Ciaurri, E. Labarga, L. Roncal, J. L. Varona, Series de Fourier no trigonométricas: una perspectiva familiar, Zubía, Monográfico 26 (2014), 39-54
L. Roncal, P. R. Stinga, Transference of fractional Laplacian regularity, Special Functions, Partial Differential Equations and Harmonic Analysis. In honor of Calixto P. Calderón, in: Springer Proceedings in Mathematics and Statistics 108, A. M. Stokolos, C. Georgakis, and W. Urbina (Eds.) (2014), 203-212
E. Fernández, L. Roncal, Los números de Ramsey y el álgebra, Gac. R. Soc. Mat. Esp. 15 (2012), 651-674
Ó. Ciaurri, E. Fernández. R. Larrea, L. Roncal, Vietè's product: a proof in the finest ancient style, College Math. J. 43 (2012), 291-296
Ó. Ciaurri, L. Roncal, J.L. Torrea, J.L. Varona, How to define the Riesz transform for Fourier-Neumann expansions?, Contribuciones científicas en honor de Mirian Andrés, Servicio de Publicaciones de la Universidad de La Rioja, ISBN 978-84-96487-50-5, Logroño, La Rioja (2010), 203-215
PhD Thesis
Weighted boundedness of operators related to the Fourier-Bessel expansions (advisor Óscar Ciaurri)