Some families of polynomial automorphisms III

We prove that the closure (for the Zariski topology) of the set of polynomial automorphisms of the complex affine plane whose polydegree is (cd−1,b,a)(cd−1,b,a) contains all automorphisms of polydegree (cd+a)(cd+a) where a,b≥2a,b≥2 and c≥1c≥1 are integers and d=ab−1d=ab−1. When b=2b=2, this result gives a family of counterexamples to a conjecture of Furter.