Carolina Vallejo Rodríguez

I am a Rita Levi Montalcini researcher (ricercatrice tipo B) at the University of Florence (UNIFI), where I work as a member of the Algebra group. I am also a member of the GNSAGA of the Istituto di Alta Matematica "Francesco Severi" (INdaM).

My main interest are the so-called Counting Conjectures, which fit into the class of global/local problems in Group Representation Theory.

Between April 2019 and June 2021 I was an assistant professor in Madrid, first at at the Universidad Carlos III de Madrid (UC3M) and later at the Universidad Autónoma de Madrid (UAM). Prior to that, I have held different postdoc positions. I was a Juan de la Cierva postdoctoral researcher at the UAM, a Severo Ochoa fellow at the Instituto de Ciencias Matemáticas (ICMAT) and a postdoc at the Simons Laufer Mathematical Science Institute (now SLMath, formerly MSRI) associated with the research program Group Representation Theory and Applications.

I completed my Ph.D. at the University of Valencia, where I worked under the supervision of Gabriel Navarro. The main goal of my Ph.D. thesis was to find explicit bijections between character sets, so that fields of values of characters were preserved.

My research is currently funded by the Rita Levi-Montalcini Programme for Young Reseachers (Ministero dell'Università e della Ricerca di Italia). Previously, I was the PI of the Spanish I+D+i project "COCO" (Counting Conjectures, PID2020-118193GA-I00).


  • We are organizing the fourth edition of the Group Theory in Florence conference that will be held at the University of Florence, July 1-3, 2024.



  1. On almost p-rational characters in principal blocks (joint work with A. Maróti, J. M. Martínez, A. A. Schaeffer Fry).

  2. In Press

  3. Principal blocks with six irreducible characters (joint work with N. N. Hung and A. A. Schaeffer Fry). To appear in Journal of Algebra (special issue in memory of Georgia Benkart). Current online version.

  4. Published

  5. The fields of values of the 2-height zero characters (joint with G. Navarro, L. Ruhstorfer and P. H. Tiep), Adv. Math. 443 (2024), 109589.
  6. A lower bound on the number of generators of a defect group , Vietnam J. Math. 51, 571–576 (2023). Special issue dedicated to Pham Huu Tiep on his 60th birthday.
  7. Relative character conductors, Archiv Math. 120 (2023), 237-244.
  8. Height zero characters in principal blocks (with N. Hung and A. A. Schaeffer Fry), J. Algebra 622 (2023), 197–219.
  9. Sylow branching coefficients and a conjecture by Malle and Navarro (joint work with E. Giannelli, S. Law and J. Long), Bull. London Math. Soc. 54 (2022), 552-567.
  10. La conjetura de pesos de Alperin, Gaceta Real Soc. Mat. Española 25 (2022) no. 1 , pp. 171-187.
  11. Principal blocks with 5 irreducible characters (joint work with N. Rizo and A. A. Schaeffer Fry), J. Algebra 585 (2021), 316-337.
  12. Characters of π '-degree and small cyclotomic fields (with E. Giannelli, N. Hung and A. A. Schaeffer Fry). Ann. Mat. Pura Appl. (4) 200 (2021), no. 3, 1055 - 1073.
  13. Characters and generation of Sylow 2-subgroups (with G. Navarro, N. Rizo and A. A. Schaeffer Fry), Represent. Theory AMS 25 (2021), 142-165.
  14. A reduction theorem for the Galois-McKay conjecture (with G. Navarro and B. Späth), Trans. Amer. Math. Soc. 373 (2020), no. 9, 6157–6183.
  15. Galois action on the principal block and cyclic Sylow subgroups (with N. Rizo and A. A. Schaeffer Fry), Algebra Number Theory 14 (2020), no. 7, 1953–1979.
  16. Character correspondences in solvable groups with a self-normalizing Sylow subgroup, J. Algebra Appl. 19 (2020), no. 10, 2050190, 8 pp.
  17. Characters of π '-degree (with E. Giannelli and A. A. Schaeffer Fry), Proc. Amer. Math. Soc. 147 (2019), no. 11, 4697-4712.
  18. Brauer correspondent blocks with one simple module (with G. Navarro and P. H. Tiep), Trans. Amer. Math. Soc. 371 (2019), no. 2, 903-922.
  19. Even degree characters in the principal block (with E. Giannelli and G. Malle), J. Pure Appl. Algebra 223 (2019), no. 2, 900–907.
  20. 2-Brauer correspondent blocks with one simple module (with G. Navarro), J. Algebra 488 (2017), 230-243.
  21. Feit numbers and p'-degree characters, J. Group Theory 19 (2016), no. 6, 1129-1136.
  22. Brauer characters and coprime action (with B. Späth), J. Algebra 457 (2016), 278-311.
  23. McKay natural correspondences of characters (with G. Navarro and P. H. Tiep), Algebra Number Theory 8 (2014), no. 8, 1839–1856.
  24. A criterium for monomiality, Rend. Sem. Mat. Univ. Pad. 131 (2014), 259–262.
  25. Certain monomial characters of p'-degree (with G. Navarro), Archiv Math.99 (2012), no. 5, 407–411.

Other Publications

  • The fields of values of the 2-height zero characters. Oberwolfach Report 19 (2023). DOI: 10.14760/OWR-2023-19.
  • Characters of finite groups. TEMat monográficos 2 (2021): Proceedings of the 3rd BYMAT Conference, pp. 1-6.
  • Restriction of characters and Sylow subgroups. Oberwolfach Report 9 (2020). DOI: 10.4171/OWR/2020/9.
  • Certain monomial characters and their subnormal constituents (with G. Navarro), Groups St. Andrews 2013, London Mathematical Society Lecture Note Series 442 (2015), 436–438.


Eugenio Giannelli, Nguyen Ngoc Hung, Stacey Law, Jason Long, Gunter Malle, Attila Maróti, J. Miquel Martínez, Gabriel Navarro, Noelia Rizo, Lucas Ruhstorfer, Mandi Schaeffer Fry, Britta Späth, Pham Huu Tiep.


Some invited talks

Some contributed talk

  • "Group Theory in Florence II", Italy. September 2018. Even degree characters in principal blocks.
  • "XI Encuentro en Teoría de Grupos", Barcelona, Spain. September 2016. La tabla de caracteres de un grupo y sus propiedades locales.
  • "Darstellungstheorie-Tage 2014", TU Kaiserslautern, Germany. November 2014. p-Rational characters and p-decomposable p-Sylow normalizers.
  • "X Encuentro en Teoría de Grupos", Sevilla, Spain. October 2014. El caso autonormalizante de la conjetura de McKay.
  • "Young Algebraists’ Conference 2014", EPFL Lausanne, Switzerland. June 2014. McKay Natural Correspondences.
  • "Groups St. Andrews 2013", St. Andrews, UK. August 2013. Certain monomial characters and their subnormal constituents.

Seminar talks

Apart from talks at conferences, I've given a number of seminar talks. I'm very grateful for each of these invitations, so that I had the opportunity to visit (in alphabetical order): Bilbao (Spain), Birmingham (UK), Cambridge (UK), Firenze (Italy), Jena (Germany), Kaiserslautern (Germany), Lausanne (Switzerland), London (UK), Madrid (Spain), Málaga (Spain), Manchester (UK), Murcia (Spain), Roma (Italy), Santa Cruz (USA) and Stuttgart (Germany).

Some beamer talks

Below you can find the slides of some beamer talks.

Conference organization

I have co-organized the following conferences.

  • (Upcoming) Group Theory in Florence IV, DIMAI, Florence (Italy). July 2024.
  • Counting Conjectures and Beyond, Isaac Newton Institute, Cambridge (UK). May 2022.
  • Groups in Madrid 2021, ICMAT, Madrid (Spain). November 2021.
  • V Congreso jóvenes investigadores de la RSME, Castellón (Spain). January 2020. (Member of the scientific committee.)
  • Groups in Madrid 2019, ICMAT, Madrid (Spain). November 2019.
  • Groups in Madrid 2018, ICMAT, Madrid (Spain). November 2018.

Research Visits

I visited the SLMath (formerly MSRI) in 2023 and 2019 as a member of their Summer Research program.

San Francisco Bay, mesmerising view from the MSRI.

I visited the Isaac Newton Institute (Cambridge) during May 2022.

Cows taking a break nearby Darwin College.

I visited the University of Florence during the spring semesters of 2020 and 2022.

Palazzo Vecchio al tramonto, Piazza della Signoria.

I spent a week visiting the Algebra group of the University of Florence in February 2019.

David, Galleria dell'Accademia di Firenze.

I spent a week in Paris visiting the Institut de Mathématiques de Jussieu-Paris Rive Gauche in June 2018.

La coucher du soleil from the outside of the Hôtel Lauzun, sur la rive nord de l'île Saint-Louisin, Paris.

I visited the TU Kaiserslautern during July 2017.

Wild raspberries in the Palatinate forest.

I visited twice the TU Kaiserslautern while completing my PhD studies (in 2014 and 2015).

The forest is especially beautiful in autumn.


I taught a course on the Burnside paqb theorem (in Spanish) as part of the Escuela JAE de Matemáticas 2021 at the ICMAT. The course was recorded and the videos are available on Youtube (through the ICMAT channel).

I was awarded a Vicent Caselles Award in 2018. (A video made for this edition can be found here and you can see a picture of the ceremony on the right.)

The Vicent Caselles awards are given by the Royal Spanish Mathematical Society and the BBVA Foundation and their aim is to «celebrate knowledge through Mathematics».

My brother José Antonio is also a mathematician. He works at the UNED (Universidad Nacional de Educación a Distancia) in Spain.

On the right you can see a picture of him delivering a talk at the ICMAT.

How to contact me

Università degli studi di Firenze
Dipartimento di Matematica e Informatica ‘Ulisse Dini’ (DIMAI)
Viale Morgagni 67/a,
50134 Firenze (IT).

You may contact me at one of the following email addresses.
  • carolina . vallejo rodriguez at unifi . it
  • carolina . vallejo at uv . es