Splitting theorem for ${\mathbb{Z}}_2^n$-supermanifolds

Smooth ${\mathbb{Z}}_2^n$-supermanifolds have been introduced and studied recently. The corresponding sign rule is given by the “scalar product” of the involved ${\mathbb{Z}}_2^n$-degrees. It exhibits interesting changes in comparison with the sign rule using the parity of the total degree. With the new rule, nonzero degree even coordinates are not nilpotent, and even (resp., odd) coordinates do not necessarily commute (resp., anticommute) pairwise. The classical Batchelor-Gawcedzki theorem says that any smooth supermanifold is diffeomorphic to the “superization” $\mathrm{\Pi }E$ of a vector bundle $E$. It is also known that this result fails in the complex analytic category. Hence, it is natural to ask whether an analogous statement goes through in the category of ${\mathbb{Z}}_2^n$-supermanifolds with its local model made of formal power series. We give a positive answer to this question.