## The Choice of the Forms of Lyapunov Functions for a Positive 2D Roesser Model

The appropriate choice of the forms of Lyapunov functions for a positive 2D Roesser model is addressed. It is shown that for the positive 2D Roesser model: (i) a linear form of the state vector can be chosen as a Lyapunov function, (ii) there exists a strictly positive diagonal matrix *P* such that the matrix *A ^{T} PA - P* is negative definite. The theoretical deliberations will be illustrated by numerical examples.