The $q$-analogues of $γ$-positivity of Eulerian polynomials via group actions

Han, Jouhet and Zeng established $q$-analogues of the $γ$-expansion formulas for Eulerian polynomials of types $A$ and $B$. Combinatorial interpretations of the corresponding coefficients$a_{n,k}(q)$ and $b_{n,k}(q)$, however, remained open. In this paper, we provide combinatorial interpretations