In mathematics, a definite bilinear form's a bilinear form B over some vector space V (with real or complex scalar field) such that the associated quadratic form » Q(x)=B(x, x) is definite, that's, has a real value with the same sign (positive or negative) for all non-zero x. According to that sign, B's called positive definite or negative definite. If Q takes both positive and negative values, the bilinear form B's called indefinite. If B(x, x) ≥ 0 for all x, B's said to be positive semidef… (More on Semidefinite)