IPM Calendar 
Wednesday 19 September 2018   Today  
Events for day: Thursday 13 September 2018    
           11:00 - 12:00     Theory Weekly Seminar(TWS)
On Variational Principle and Canonical Structure of Gravitational Theory


In this talk, we analyze the variation of the gravitational action on a bounded region of spacetime, whose boundary contains segments with various characters including null. We develop a systematic approach to decompose the derivative of metric variations into orthogonal and tangential components with respect to the boundary and express them in terms of variations of geometric objects associated to the boundary hypersurface. We suggest that a double-foliation of spacetime provides a natural and useful set-up for treating the general problem and clarifies the assumptions and results in specialized ones. In this set-up, we are able to obtain th ...