4 papers
A Note on Additive Diameter
Ernesto Ingrosso
We record two results on additive diameters of group representations. First we give a corrected version of Proposition 5.3 from the first arXiv version of arXiv:2504.07573. Let $0<…
On the independence of permutation characters
M. Brescia, E. Ingrosso, M. Trombetti
Let be a finite group. For every subgroup , let be the permutation character of the action of on the left cosets of . We prove that the characters ,…
Hopficity of profinite completions of abelian groups
M. Brescia, E. Ingrosso, M. Trombetti
We determine exactly when the profinite completion of an arbitrary abelian group is topologically Hopfian. For an abelian group , we prove that \[ \widehat A \text{ is topologic…
A Torsion-free Supersoluble Group with Trivial Outer Automorphism Group
Mattia Brescia, Ernesto Ingrosso, Marco Trombetti
We give a negative solution to Problem~13.23 of the Kourovka Notebook. We construct a torsion-free group of Hirsch length admitting a finite series \[ 1=G_0\triangleleft G…