@techreport {Nilssen.2005.1,
	title = {Weakly Positve Definite Matrices},
	number = {2005-07},
	year = {2005},
	publisher = {Simula Research Laboratory},
	abstract = {A weakly positive definite matrix is defined to be a matrix which can be written as a product of two positive definite matrices. This paper proves that a matrix is weakly positive definite if and only if the real eigenvalues are positive. The main components of the proof are Schur decomposition and mathematical induction.},
	author = {Nilssen, Trygve Kastberg}
}
