Noelia Rizo

activity

20162025

most citedGalois action on the principal block and cyclic Sylow subgroups

16 citations · 16 across the 14 of their papers we have counts for

collaborators

18 papers

math.RT2025

Height zero characters and Galois automorphisms

Alexander Moretó, Noelia Rizo, Gabriel A. L. Souza

Let $G$ be a finite group and let $p$ be a prime. In this paper, we prove a strengthened version of Brauer's height zero conjecture for the principal $p$ -block of $G$ that takes th…

math.RT2025

Character Values of $p$ -solvable groups on picky elements

Alexander Moretó, Gabriel Navarro, Noelia Rizo

A new conjecture on characters of finite groups, related to the McKay conjecture, was proposed recently by the first and third authors. In this paper, we prove it for $p$ -solvable…

math.RT2024

Decomposition numbers in the principal block and Sylow normalisers

Gunter Malle, Noelia Rizo

If G is a finite group and p is a prime number, we investigate the relationship between the p-modular decomposition numbers of characters of height zero in the principal p-block of…

math.GR2024

Characters and Sylow $3$ -subgroup abelianization

Eugenio Giannelli, Noelia Rizo, A. A. Schaeffer Fry +1

We characterize when a finite group G possesses a Sylow 3-subgroup P with abelianization of order 9 in terms of the number of height zero characters lying in the principal 3-block…

math.GR2023

Brauer's problem 21 for principal blocks

Alexander Moretó, Noelia Rizo, A. A. Schaeffer Fry

Problem 21 of Brauer's list of problems from 1963 asks whether for any positive integer k there are finitely many isomorphism classes of groups that occur as the defect group of a…

math.GR2023

The blocks with five irreducible characters

J. Miquel Martínez, Noelia Rizo, Lucia Sanus

Let $G$ be a finite group, $p$ a prime and $B$ a Brauer $p$ -block of $G$ with defect group $D$ . We prove that if the number of irreducible ordinary characters in $B$ is $5$ then $D…

math.RT2023

Minimal heights and defect groups with two character degrees

Gunter Malle, Alexander Moretó, Noelia Rizo

Conjecture A of \cite{EM14} predicts the equality between the smallest positive height of the irreducible characters in a $p$ -block of a finite group and the smallest positive heig…

math.GR2022

Principal blocks for different primes, II

Gabriel Navarro, Noelia Rizo, A. A. Schaeffer Fry

If G is a finite group, we have proposed new conjectures on the interaction between different primes and their corresponding Brauer principal blocks. In this paper, we give strong…

math.GR2022

Principal blocks for different primes, I

Gabriel Navarro, Noelia Rizo, A. A. Schaeffer Fry

We propose new conjectures about the relationship between the principal blocks of finite groups for different primes and establish evidence for these conjectures.

math.GR2021

The blocks with four irreducible characters

J. Miquel Martínez, Noelia Rizo, Lucía Sanus

Suppose that $B$ is a Brauer $p$ -block with defect group $D$ . If $B$ exactly contains 4 irreducible characters, then we show that $D$ has order 4 or 5, assuming the Alperin--McKay…

math.GR2021

Kernels of p'-degree irreducible characters

Alexander Moretó, Noelia Rizo

We prove a p'-version of a classical theorem of Broline and Garrison. As a consequence, we obtain results on p-parts of character codegrees.

math.GR2020

Principal blocks with 5 irreducible characters

Noelia Rizo, Amanda Schaeffer Fry, Carolina Vallejo

We show that if the principal p-block of a finite group G contains exactly 5 irreducible ordinary characters, then a Sylow p-subgroup of G has order 5, 7 or is isomorphic to one of…

math.RT2020

Groups with few $p^{'}$ -character degrees in the principal block

Eugenio Giannelli, Noelia Rizo, Benjamin Sambale +1

Let p be a prime larger than 3 and let G be a finite group. We prove that G is p-solvable of p-length at most 2 if there are at most two distinct character degrees relatively prime…

math.RT2019★ 16 cited

Galois action on the principal block and cyclic Sylow subgroups

Noelia Rizo, A. A. Schaeffer Fry, Carolina Vallejo

We characterize finite groups having a cyclic Sylow p-subgroup in terms of the action of a specific Galois automorphism on the principal p-block for p=2,3. We show that the analog…

math.GR2019

Groups with few $p^{'}$ -character degrees

Eugenio Giannelli, Noelia Rizo, Mandi Schaeffer Fry

We prove a variation of Thompson's Theorem. Namely, if the first column of the character table of a finite group $G$ contains only two distinct values not divisible by a given prim…

math.RT2018

Unitary t-groups

Eiichi Bannai, Gabriel Navarro, Noelia Rizo +1

Relying on the main results of [Guralnick-Tiep], we classify all unitary $t$ -groups for $t \geq 2$ in any dimension $d \geq 2$ . We also show that there is essentially a unique unit…

math.RT2018

p-Blocks Relative to a Character of a Normal Subgroup

Noelia Rizo

Let G be a finite group, let N be a normal subgroup of G, and let theta in Irr(N) be a G-invariant character. We fix a prime p, and we introduce a canonical partition of Irr(G|thet…

math.RT2016

Certain irreducible characters over a normal subgroup

Gabriel Navarro, Noelia Rizo

We extend the Howlett-Isaacs theorem on the solvability of groups of central type taking into account actions by automorphisms. Then we study certain induced characters whose const…