GRJunction is a GRTensorII package for perfoming junction and thin-shell calculations in general relativity.
GRJunction allows users to specify a surface in a spacetime and determine quantities such as:
The first and second fundamental forms
Hamiltonian and ADM constraints
Two surfaces can be joined and then the user may calculate a variety of quantities including:
Darmois-Israel junction conditions (timelike/spacelike surfaces)
Barrabès-Israel formalism (null surfaces)
Stress-energy of the surface layer
Conservation and evolution laws for the surface
GRJunction is currently at our old site
here
.