BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20250812T154251EDT-1270hUe8jB@132.216.98.100 DTSTAMP:20250812T194251Z DESCRIPTION:A Look at Some Mathematics Research Problems in General Relativ ity\n\n\nAbstract: \n\nIn 1915\, Einstein (and Hilbert) formulated the equ ations of general relativity\, the Einstein Equations\, as a geometric des cription of what we experience as gravity\, displacing Newton's theory of gravity. Already by 1916\, it was realized that the equations predict that gravitationally interacting bodies will emit radiation at the speed of li ght that will carry energy away from the interaction. Unlike other types o f radiation\, this radiation is actually a 'ripple' in space (and time). M assive interactions that occur at relatively close ranges\, such as in-spi raling and colliding black holes\, emit enough radiation that they could p otentially be detected by a device that we could build using late 20th/ear ly 21st century technology. Such a device was built\,called LIGO (Laser In terferometer Gravitational-Wave Observatory). At more than $600M\, it is t he most ambitious and expensive NSF project ever undertaken.On 11 February 2016\, it was announed that LIGO detected a clear\, unambiguous\,loud and violent inspiral\, collision\, merger\, and ringdown of a binary black ho le pair\, each of which had a solar mass in the range 10-50\, with roughly the equivalent of three solar masses in energy released as gravitational radiation.This radiation traveled outward from the collision at the speed of light\, reaching the LIGO detectors on earth roughly 1.3 billion years later. Three additional detections were made between February 2016 and Sep tember 2017\,the most recent of which was confirmed by the new VIRGO detec tor in Europe.Last week\, the Nobel Prize in Physics was awarded to three of the key researchers that made LIGO possible.\n\nHow do LIGO/VIRGO scien tists know what they are detecting? The answer is that the signals detecte d by the devices were shown\, after extensive data analysis and computer s imulations of the Einstein evolution and constraint equations\, to be a ve ry close match to simulations of wave emission from very particular types of binary collisions. In this lecture\, we will examine some fundamental m athematics research questions involving the Einstein constraint equations. We begin with an overview of the most useful mathematical formulation of the constraint equations\, and then summarize the known existence\, unique ness\, and multiplicity results through 2008. We then present a number of new existence and multiplicity results developed since 2008 that substanti ally change the solution theory for the constraint equations. We then shif t gears and consider Petrov-Galerkin type approximation methods for develo ping 'provably good' numerical methods for solving this type of system. We examine how one proves rigorous error estimates for particular classes of numerical methods\, including both classical finite element methods and n ewer methods from the finite element exterior calculus.\n DTSTART:20171011T190000Z DTEND:20171011T200000Z LOCATION:Room 1205\, Burnside Hall\, CA\, QC\, Montreal\, H3A 0B9\, 805 rue Sherbrooke Ouest SUMMARY:Michael Holst URL:/mathstat/channels/event/michael-holst-275000 END:VEVENT END:VCALENDAR