## Alexandru Ciolan

Mathematical Institute
University of Cologne
Weyertal 86-90
50931 Cologne
Germany
Office: Gyrhofstr. 8b 0.5
Telephone: +49 (0)221 470 1886
Office hours: Thursday, 14:00-15:00
E-mail: aciolan AT math.uni-koeln.de

As of August 2017, I am a PhD student of Prof. Dr. Kathrin Bringmann at the University of Cologne. My main research interests are in number theory, particularly in modular forms and partitions. Further interests lie in more elementary topics: cyclotomic polynomials, numerical semigroups, discriminators of integer sequences.

Previously I obtained my Master's degree from the University of Bonn and my Bachelor's degree from Jacobs University Bremen.

### Teaching

Summer 2018: Seminar Elliptische Funktionen

### Publications and Preprints

Browkin's discriminator conjecture, to appear in Colloq. Math.;
with Pieter Moree.

Counting terms $U_n$ of third order linear recurrences $U_n=u^2+nv^2$, J. Ramanujan Math. Soc. 32 (2017), No. 2, 165-183;
with Florian Luca and Pieter Moree.

Cyclotomic coefficients: gaps and jumps, J. Number Theory 163 (2016), 211-237;
with Oana-Maria Camburu, Florian Luca, Pieter Moree and Igor E. Shparlinski.

Cyclotomic numerical semigroups, SIAM J. Discrete Math. 30 (2016), No. 2, 650-668;
with Pedro A. García-Sánchez and Pieter Moree.

Convergence properties of the classical and generalized Rogers-Ramanujan continued fraction, Res. Number Theory 1 (2015), Art. 15, 18 pp.;
with Robert A. Neiss.

Olimpiadele de matematica cls. IX-XII, 2008 (in Romanian, Olympiads textbook; translation to English: Mathematical Olympiads for the 9-12th grades, 2008), GIL Publishing House, Zalau, 2008;
with Dragos Dumitrescu et al.

### Talks Given

Cyclotomic numerical semigroups, SFB Retreat, Sept. 2017, Maria in der Aue, Germany.

Gaps and jumps in cyclotomic coefficients, ELAZ 2016 - Conference on Elementary and Analytic Number Theory, Sept. 2016, Strobl am Wolfgangsee, Austria.

Cyclotomic numerical semigroups I, International Meeting on Numerical Semigroups with Applications, July 2016, Levico Terme, Italy.

Convergence properties of the classical and generalized Rogers-Ramanujan continued fraction, Discoverers avant le PhD, Sept. 2015, MPIM Bonn, Germany.

Cyclotomic numerical semigroups, International Meeting on Numerical Semigroups, Sept. 2014, Cortona, Italy.

### Selected Conferences and Programs Attended

SFB Retreat, Sept. 2017, Maria in der Aue, Germany.

Modular forms are everywhere, May 2017, Bonn, Germany.

ELAZ 2016 - Conference on Elementary and Analytic Number Theory, Sept. 2016, Strobl am Wolfgangsee, Austria.

International Meeting on Numerical Semigroups with Applications, July 2016, Levico Terme, Italy.

Introductory School on Moduli Spaces, Sept. 2015, Bonn, Germany.

Mathematische Arbeitstagung, Sept. 2015, Bonn, Germany.

Automorphic Forms - Advances and Applications, May 2015, CIRM-Marseille, France.

Spring School - Characters of Representations and Modular Forms, March 2015, Bonn, Germany.

Cologne Young Researchers in Number Theory Program (organized by Larry Rolen), Feb.-April 2015, University of Cologne, Germany.

The 2nd Heidelberg Laureate Forum, Sept. 2014, Heidelberg, Germany.

International Meeting on Numerical Semigroups, Sept. 2014, Cortona, Italy.