Ein Verfahren zur Stabilitätsfrage bei Matrizen-Eigenwertproblemen

Given the eigenvalue problem (A−λE) x=0 for real or complex matricesA the number of eigenvalues λ with positive real parts is determined without evaluating the caracteristical polynomial. A proceeding is developed here to transform the given matrixA into a reduced form by applying a finite series of elementary transformations upon the matrix. The elements of the reduced matrix allow immediately to solve the problem.