“…If f (x, t) = f 0 (t) with f 0 : R + → R, then the orthogonal expansions of f on the conic domain becomes the classical Laguerre expansions on R + , which has been studied extensively in the literature; see [1,7,8,9,10,14,17,18] and, for some more recent works, see [2,11,12,15] and the references therein. As in the study of classical Laguerre expansions, our study relies on intrinsic properties of orthogonal polynomials that hold only for particular weight functions and special domains.…”