Around the Andreadakis-Johnson filtration

Yusuke Kuno

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arXiv · 2608.26934

Around the Andreadakis-Johnson filtration

Yusuke Kuno

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Abstract

The Andreadakis-Johnson filtration and its associated construction, known as the Johnson homomorphism, are useful tools in group theory. They provide a step-by-step approach to studying the automorphisms of a given group. After explaining the basics we survey both classical and recent results around the Andreadakis-Johnson filtration, with emphasis on the mapping class group of a once-bordered surface.

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Yusuke Kuno. 2026-08-27. Around the Andreadakis-Johnson filtration. https://arxiv.org/abs/2608.26934

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