If all the Eigenvalues of a Real Matrix A have Real Parts, then to an
arbitrary negative definite quadratic form
there corresponds a positive
definite quadratic form
such that if one takes
Gradshteyn, I. S. and Ryzhik, I. M. Tables of Integrals, Series, and Products, 5th ed. San Diego, CA:
Academic Press, p. 1122, 1979.