Ricard Riba

activity

20192026

collaborators

3 papers

math.GT2026

Image of the third Johnson homomorphism

Quentin Faes, Ricard Riba

In this note we show that the image of the third Johnson homomorphism $τ_{3}$ coincides with the kernel of Morita's trace map for the case of a surface of genus $g$ with one boundary…

math.GT2025

A Parametrization of Integral Homology 3-Spheres by the Fourth Johnson subgroup

Ricard Riba

By results of Morita, Pitsch and, more recently, Faes, it is known that any integral homology 3-sphere can be constructed as a Heegaard splitting with a gluing map an element of th…

math.GR2019

Automorphisms of descending mod-p central series

Ricard Riba

Given a free group $Γ$ of finite rank $n$ and a prime number $p,$ denote by $Γ_{k}^{∙}$ the $k^{th}$ layer of the Stallings ( $∙ = S$ ) or Zassenhaus ( $∙ = Z$ ) $p$ -cen…