Geometry & Topology

Addendum to: Commensurations of the Johnson kernel

Tara E Brendle and Dan Margalit

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Abstract

Let K(S) be the subgroup of the extended mapping class group, Mod(S), generated by Dehn twists about separating curves. In our earlier paper, we showed that Comm(K(S))Aut(K(S))Mod(S) when S is a closed, connected, orientable surface of genus g4. By modifying our original proof, we show that the same result holds for g3, thus confirming Farb’s conjecture in all cases (the statement is not true for g2).

Article information

Source
Geom. Topol., Volume 12, Number 1 (2008), 97-101.

Dates
Received: 13 September 2007
Accepted: 12 October 2007
First available in Project Euclid: 20 December 2017

Permanent link to this document
https://projecteuclid.org/euclid.gt/1513800014

Digital Object Identifier
doi:10.2140/gt.2008.12.97

Mathematical Reviews number (MathSciNet)
MR2377246

Zentralblatt MATH identifier
1128.57303

Subjects
Primary: 20F36: Braid groups; Artin groups

Keywords
Johnson kernel Torelli group automorphisms abstract commensurator

Citation

Brendle, Tara E; Margalit, Dan. Addendum to: Commensurations of the Johnson kernel. Geom. Topol. 12 (2008), no. 1, 97--101. doi:10.2140/gt.2008.12.97. https://projecteuclid.org/euclid.gt/1513800014


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References

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