Reduction of linear kinetic systems with multiple scales

We present a simple and general reduction algorithm for stiff monomolecular kinetic systems. The reduction is based on algebraic techniques and consis ts in eliminating the fastest dynamics in the initial system without any ch ange of basis. This process is systematic and is not based on chemical conv entional assumptions or on singular perturbation techniques. Systems can be reduced even if they are not in the Tikhonov form. This reduction process is applied to kinetic systems with kinetic constants belonging to different scales. Error estimates for all species are given. Numerical tests are per formed.