This page presents a Python code to demonstrate the proof of stability with ellispoids. After describing a nonlinear discrete-time system, this numerical method finds a ellipsoid positive invariant with respect to the system and use this ellipsoid to prove the exponential stability of the system.
Download the Python code: https://github.com/MLouedec/Demo_discrete_time_stability_proof
Dependencies: numpy, scipy, sympy, matplotlib and codac