The handlebody group and the images of the second Johnson homomorphism - Archive ouverte HAL
Pré-Publication, Document De Travail Année : 2022

The handlebody group and the images of the second Johnson homomorphism

Quentin Faes
  • Fonction : Auteur
  • PersonId : 1124741

Résumé

Given an oriented surface bounding a handlebody, we study the subgroup of its mapping class group defined as the intersection of the handlebody group and the second term of the Johnson filtration: $\mathcal{A} \cap J_2$. We introduce two trace-like operators, inspired by Morita's trace, and show that their kernels coincide with the images by the second Johnson homomorphism $\tau_2$ of $J_2$ and $\mathcal{A} \cap J_2$, respectively. In particular, we answer by the negative to a question asked by Levine about an algebraic description of $\tau_2(\mathcal{A} \cap J_2)$. By the same techniques, and for a Heegaard surface in $S^3$, we also compute the image by $\tau_2$ of the intersection of the Goeritz group $\mathcal{G}$ with $J_2$.

Dates et versions

hal-03548510 , version 1 (30-01-2022)

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Citer

Quentin Faes. The handlebody group and the images of the second Johnson homomorphism. 2022. ⟨hal-03548510⟩
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