Expanding the quasisymmetric Macdonald polynomials in the fundamental basis

The quasisymmetric Macdonald polynomials G gamma ( X ; q, t ) were recently introduced by the first and second authors with Haglund, Mason, and Williams in [3] to refine the symmetric Macdonald polynomials P lambda (X ; q, t ) with the property that G gamma ( X ; 0,0) equals QS gamma (X ) , the quasisymmetric Schur polynomial of [9]. We derive an expansion for G gamma ( X ; q, t ) in the fundamental basis of quasisymmetric functions.