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arXiv · 1512.04268

Point-like limit of the hyperelliptic Zhang-Kawazumi invariant

Robin de Jong
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Abstract

The behavior near the boundary in the Deligne-Mumford compactification of many functions on the moduli space of pointed Riemann surfaces can be conveniently expressed using the notion of "point-like limit" that we adopt from the string theory literature. In this note we study a function on the moduli space of Riemann surfaces that has been introduced by N. Kawazumi and S. Zhang, independently. We show that the point-like limit of the Zhang-Kawazumi invariant in a family of hyperelliptic Riemann surfaces in the direction of any hyperelliptic stable curve exists, and is given by evaluating a combinatorial analogue of the Zhang-Kawazumi invariant, also introduced by Zhang, on the dual graph of that stable curve.

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Robin de Jong. 2015-12-14. Point-like limit of the hyperelliptic Zhang-Kawazumi invariant. https://doi.org/10.4310/pamq.2015.v11.n4.a4

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