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December 2, 2025 By GeometryAdmin

Qiu Shi Wang to give geometry seminar 26/01/26

Qiu Shi Want (Oxford) will speak in the geometry seminar on 26th January, at 2pm on 26th January 2026. Qiu Shi’s title is “Computer-assisted construction of SU(2)-invariant cohomogeneity one Einstein metrics,” and his abstract is below.

In this talk, I will present a construction of a new family of SU(2)-invariant complete negative Einstein metrics on the complex line bundle O(-4) over CP^1. The metrics are conformally compact and generically neither Kähler nor self-dual. The proof involves using rigorous numerical techniques (Chebyshev polynomials and arbitrary-precision interval arithmetic) to produce an approximate Einstein metric to high precision in a bounded region near the singular orbit, then perturbing it to a genuine Einstein metric using fixed-point methods. At the boundary of this region, we show that the latter metric is sufficiently close to hyperbolic space so that it extends to a complete, asymptotically hyperbolic Einstein metric. Our construction is based on previous work of Buttsworth—Hodgkinson.

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Département de mathématiques
Université libre de Bruxelles CP 218
Boulevard du Triomphe, Bruxelles 1050,
Belgium

Getting here

The department of mathematics is in building NO, on the Campus de la Plaine, of the Université libre de Bruxelles. The geometry group is on the 7th floor. This page has a map of the campus as well as information on how to reach it via public transport. See the STIB website for more information on public transport in Brussels.

Image credits

Polished ammonite fossil, by Kara Stenberg, Creative Commons licence CC BY-NC 2.0.

Model of 3D projection of a 120-cell, by Edmund Harriss.

The root system of the exceptional Lie algebra E8. By Jared Tarbell, Creative Commons Licence CC BY 2.0.

Getting here

The department of mathematics is in building NO, on the Campus de la Plaine, of the Université libre de Bruxelles. The geometry group is on the 7th floor. This map shows NO, as well as the metro station Delta and entrance 2, which is right by the stop for the number 71 and 72 buses. The number 95 also stops a short walk from the department. See the STIB website for more information on public transport in Brussels.

Image credits

Polished ammonite fossil, by Kara Stenberg, Creative Commons licence CC BY-NC 2.0.

Model of 3D projection of a 120-cell, by Edmund Harriss.

The root system of the exceptional Lie algebra E8. By Jared Tarbell, Creative Commons Licence CC BY 2.0.

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