In this paper, we study the stability of the zero equilibria of the following systems of difference equations:
xn+1=a1xn+b1yne−xn,yn+1=a2yn+b2zne−yn,zn+1=a3zn+b3xne−zn,
xn+1=a1yn+b1xne−yn,yn+1=a2zn+b2yne−zn,zn+1=a3xn+b3zne−xn,
where a1, a2, a3, b1, b2, and b3 are real constants, and the initial values x0, y0, and z0 are real numbers. We study the stability of those systems in the special case when one of the eigenvalues of the coefficient matrix of the corresponding linearized systems is equal to −1 and the remaining eigenvalues have absolute value less than 1, using centre manifold theory.