Orthogonal polynomials, special functions, the $q$- analogous.
Main publications:
L. Khériji and P. Maroni, “The $H_q$-classical orthogonal polynomials”, Acta Appl. Math., 71 (2002), 49–115
L. Khériji, “An introduction to the $H_q$-semiclassical
orthogonal polynomials”, Methods Appl. Anal., 10:3 (2003), 387–412
A. Ghressi and L. Khériji, “Some new results about a symmetric
$D$-semiclassical linear form of class one”, Taiwanese J. Math., 11:2 (2007), 371–382
A. Ghressi and L. Khériji, “Orthogonal $q$-polynomials related to perturbed linear form”, Appl. Math. E-Notes., 7 (2007), 111–120
A. Ghressi and L. Khériji, “On the $q$-analogue of Dunkl operator ant its Appell classical orthogonal polynomials”, Int. J. Pure Appl. Math., 39:1 (2007), 1–16