NOTE ON TEST FUNCTIONS FOR STABILITY
William Jolly Duncan · The Quarterly Journal of Mechanics and Applied Mathematics · 1955
Simple relations are established between the determinantal forms of the test functions of a given polynomial and of certain related polynomials. These relations are applied to the computation of the test functions and, in particular, of the critical test determinant. It is shown that when the characteristic equation can be factorized, as when certain couplings are absent, the critical test determinant contains an irrelevant factor which is the eliminant of a pair of algebraic equations.