To be used in future
 Section A.3: Gaussian Integrals Up Appendix A: Useful Mathematics Section A.5: Matrix algebra 

A.4 Vector calculus

Basic relations
Stokes theorem
( is the curve bounding the surface .)
Divergence theorem
( is the surface of the volume )
 Section A.3: Gaussian Integrals Up Appendix A: Useful Mathematics Section A.5: Matrix algebra