Radu Toma
I am a fourthyear doctoral student in the Analytic Number Theory and Automorphic Forms group
at the University of Bonn, under the supervision of Prof. Dr. Valentin Blomer.
I am particularly interested in automorphic forms in higher rank and the supnorm problem, but also more classical number theory.
Starting autumn 2024 I'll be a postdoc in Paris with Farrell Brumley.
Here is my CV. You can reach me at
toma 🙈 math.unibonn.de
Publications and preprints

The supnorm problem for newforms of large level on PGL(n),
Arxiv preprint: https://arxiv.org/abs/2401.02741

Hybrid bounds for the supnorm of automorphic forms in higher rank,
Trans. Amer. Math. Soc. 376 (2023),
Arxiv preprint: https://arxiv.org/abs/2111.09923

Estimates for representation numbers of binary quadratic forms and Apollonian circle packings,
Journal of Number Theory, vol. 214, September 2020, pp. 399–413, doi:10.1016/j.jnt.2020.03.005
[ preprint ]
Notes

AtkinLehner operators for GL(n) * now part of my paper The supnorm problem for newforms of large level on PGL(n),
This note explains how we may generalise the classical definition of AtkinLehner operators to GL(n) for n > 2. In particular, it contains a proof that the normaliser of the Hecke congruence group is trivial for n > 2, a definition for the Fricke involutions, and the (unfortunate) conclusion that there are no other AtkinLehner operators in these cases. [ pdf ]

The spectral theory of automorphic forms on SL(2, Z),
Part III Essay, University of Cambridge. This essay presents a proof of the spectral theorem for SL(2, Z). [ pdf ]

The arithmetic of binary quadratic forms,
Bachelor's thesis, GeorgAugustUniversität Göttingen. This thesis presents the theory of binary quadratic forms with a focus on representation numbers, nonfundamental discriminants, and an application to Apollonian circle packings. [ pdf ]
Current & Upcoming Activities

Workshop Distribution of orbits: Arithmetics and Dynamics
Switzerland, 8.07  12.07.2024
 Defence 16th of September.
Past Activities
 Organising HCM career event for docs and postdocs: April 19th!

Talk at the Texas A&M Number Theory Seminar
Online, 26.03.2024

Talk at the Renyi Number Theory Seminar
Budapest, 7.03.2024

Number theory learning seminar on the modern ergodic method for proving equidistribution results
Uni Bonn, WS23/24

Talk at the Copenhagen Number Theory Seminar
Zoom, 11.12.2023

Automorphic Forms and Lfunctions of higher rank
London, 1115.09.2023

Talk at YRANT
Cambridge, 0608.09.2023

Analysis of Automorphic Forms and LFunctions in Higher Rank
Oberwolfach, 08.0502.06.2023

Talk at Arithmetic Statistics in Automorphic Forms and Analytic Number Theory
Lausanne, 0509.06.2023

Talk at the Number theory seminar of ETH Zürich,
Zürich, 28.10.2022

Research stay at EPFL, Chair of Analytic Number Theory,
Lausanne, September  December 2022

Talk at
Building Bridges 5,
Sarajevo, 09.08.2022
On the supnorm of automorphic forms in higher rank

Talk at the
Workshop for Young Researchers in Mathematics, Simion Stoilow Institute of Mathematics of the Romanian Academy,
online, 05.05.2022
On the supnorm of automorphic forms

Talk (recorded) at the
Renyi Automorphic Forms Seminar,
online, 05.05.2022
Hybrid bounds for the supnorm of automorphic forms in higher rank (slides)

Talk at
ENTR Seminar,
online, 20.04.2022
On the supnorm of automorphic forms
 Coorganised a conference, Young Scholars in the Analytic Theory of Numbers and Automorphic Forms, 2829 March 2022, at the University of Bonn, for doctoral students and postdocs.

Talk at
Cambridge Junior Algebra/Number Theory seminar,
online, 4.02.2022
How loud is an arithmetic drum?

Talk at
Laboratoire Paul Painlevé, Seminaire d'Arithmétique & study group on Lfunctions
Lille, 21.10.2021
Estimates for binary quadratic forms and Appollonian circle packings
 Studentischer Vertreter im Vorstand des Mathematischen Instituts, 20212022
 TA for Einführung in die Algebra, WS 21/22

Video for 3blue1brown's Sommer of Math Exposition:
The video explains in an accessible way (highschool / firstyear uni level) how roots of unity and cyclotomic polynomials can help us solve a problem about comparing weights of several objects simultaneously.
Contact
Radu TomaMathematisches Institut
Endenicher Allee 60
53115 Bonn, Germany
Office: N1.009
EMail: toma (at) math.unibonn.de
News
Bonn mathematics performs excellently again in QS ranking
Stefan Schwede is invited speaker at the ECM 2024 in Sevilla
Jessica Fintzen wins Cole Prize
Regula Krapf receives university teaching award
Catharina Stroppel joined the North RhineWestphalia Academy for Sciences and Arts
Daniel Huybrechts receives the Compositio Prize for the periode 20172019
Catharina Stroppel receives Gottfried Wilhelm Leibniz Prize 2023
Grants for Mathematics students from Ukraine
Jessica Fintzen is awarded a Whitehead Prize of the London Mathematical Society
Peter Scholze elected as Foreign Member of the Royal Society