Wadge degrees of ${\Delta }_2^0$ omega-powers

Olivier Finkel, Dominique Lecomte

We provide, for each natural number $n$ and each class among $D_n({\Sigma }_1^0)$, ${\bar{D}}_n({\Sigma }_1^0)$ and $D_{2n+1}({\Sigma }_1^0)\oplus {\bar{D}}_{2n+1}({\Sigma }_1^0)$, a regular language whose associated om…