2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/149577We introduce the quantum multi-Schur functions, quantum factorial Schur functions and quantum Macdonald polynomials. We prove that for restricted vexillary permutations the quantum double Schubert polynomial coincides with some quantum multi-Schur function and prove a quantum analog of the Nagelsbach-Kostka and Jacobi-Trudi formulae for the quantum double Schubert polynomials in the case of Grassmannian permutations. We prove, also, an analog of the Billey-Jockusch-Stanley formula for quantum Schubert polynomials. Finally we formulate two conjectures about the structure of quantum double and quantum Schubert polynomials for 321-avoiding permutations.17pages, PlainTeX, revised version contains additional examples, references, and new Section 4 about the determinantal formulae for quantum double Schubert polynomialsQuantum Algebratext