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Timeline for Comparison of two monodromies

Current License: CC BY-SA 4.0

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Apr 18, 2021 at 9:30 comment added Francesco Polizzi Maybe one can use in some way (at least when $\gamma$ has order $2$) the fact that the elementary abelian group $V=G/\langle \gamma \rangle$ acts freely on the quotient varieties $\Sigma_g/\langle \gamma \rangle$ and $X /\langle \gamma \rangle$
Apr 18, 2021 at 7:38 comment added Francesco Polizzi Ah, ok. In my situation, since I am assuming actual ramification, then $\gamma$ is non-trivial (and moreover I have that $G/\langle \gamma \rangle$ is elementary abelian).
Apr 17, 2021 at 22:47 comment added Will Sawin @FrancescoPolizzi I mean, if you let $\gamma$ be trivial, the abelian case is OK.
Apr 17, 2021 at 22:32 comment added Francesco Polizzi Abelian groups cannot occur, since I want ramification on the diagonal, hence the image of the element $\gamma$, that is a non-trivial commutator in $\pi_1(\Sigma_g \times \Sigma_g - \Delta)$, must give a non-trivial commutator in $G$. For extra-special $p$-groups, this means that the image of $\gamma$ must lie in the center $Z(G) \simeq \mathbb{Z}_p$. Maybe, for extra-special $2$-groups one can say something more precise about the monodromies, since in that case the image of $\gamma$ is the unique generator of the center $Z(G) \simeq \mathbb{Z}_2$.
Apr 17, 2021 at 22:26 comment added Will Sawin @FrancescoPolizzi I currently can't see how to do any case except for abelian groups, which perhaps suggests that extra-special groups are not far off, but I don't see how to extend it yet.
Apr 17, 2021 at 22:11 comment added Francesco Polizzi Thank you for the nice answer. Can you see any condition on the finite group $G$ implying equality? For instance, in my case $G$ is extra-special.
Apr 17, 2021 at 22:06 history answered Will Sawin CC BY-SA 4.0