# Mathematics Colloquia and Seminars

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### Spinning Black Holes and CR 3-Folds

**QMAP Seminar**

Speaker: | Curtis Porter, North Carolina State |

Location: | 2112 MSB |

Start time: | Fri, Mar 15 2019, 11:00AM |

Some physically significant solutions to Einstein's field equations are spacetimes which are foliated by a family of curves called a shear-free null geodesic congruence (SFNGC). Examples include models of gravitational waves that were recently detected, and rotating black holes. The properties of a SFNGC induce a CR structure on the 3-dimensional leaf space of the foliation. The Kerr Theorem says that the family of metrics associated to a SFNGC contains a conformally flat representative iff the corresponding CR structure is embeddable in a real hyperquadric. Using Cartan's method of moving frames, we can classify those Levi-nondegenerate CR 3-folds which are embeddable in the hyperquadric.