analytic functions differential subordination subordination Hankel determinant exponential function modulus of continuity starlike functions Hadamard product Janowski function Mathematics & science Mittag–Leffler function Research & information: general Ulam stability analytic function convex functions generating functions partial sum q-derivative (or q-difference) operator q-hypergeometric functions spectral decomposition starlike and q-starlike functions starlike function univalent functions upper bound (p (δ,q)-neighborhood ?-convex function ?-generalized Hurwitz-Lerch zeta functions ?-generalized Hurwitz–Lerch zeta functions Adomian decomposition method