Computation of Domains of analyticity of lower dimensional tori in a weakly dissipative Froeschl\'e map

We consider a Froeschl\'e map and we add a weak dissipation of the form λ(ε) = 1- ε³, where ε is the parameter of perturbation. We compute formal expansions of lower dimensional tori, both in the conservative and weakly dissipatives cases, and use them to estimate the shape of their domains of analyticity as functions of ε. Our results support conjectures in the literature.