Some new classes of permutation polynomials and their compositional inverses

We focus on the permutation polynomials of the form L(X)+ₘ³ᵐ(X)ˢ over q³, where q is the finite field with q=pᵐ elements, p is a prime number, m is a positive integer, ₘ³ᵐ is the relative trace function from _p³ᵐ to _pᵐ, $L(X)$ is a linearized polynomial over _q³, and $s>1$ is a positive integer. More precisely, we present six new classes of permutation polynomials over q³ of the aforementioned form: one class over finite fields of even characteristic, three classes over finite fields of odd characteristic, and the remaining two over finite fields of arbitrary characteristic. Furthermore, we show that these classes of permutation polynomials are inequivalent to the known ones of the same form. We also provide the explicit expressions for the compositional inverses of each of these classes of permutation polynomials.