Letters to the Editor on the Paper ‘Fault Detection and Isolation for State Affine Systems’ by H. Hammouri, M. Kinnaert and E. H. El Yaagoubi

In this note we show how to test whether or not certain algebraic equations derived in the paper 'Fault Detection and Isolation for State Affine Systems', by H. Hammouri, M. Kinnaert, E.H. El Yaagoubi, are solvable and to describe a solution method. Test and solution rely upon elementary linear algebraic techniques.