Power Series Solutions of Singular (q)-Differential Equations
  We provide algorithms computing power series solutions of a large class of differential or $q$-differential equations or systems. Their number of arithmetic operations grows linearly with the precision, up to logarithmic terms. 
Alin Bostan and Muhammad F. I. Chowdhury and Romain Lebreton and Bruno   Salvy and \'Eric Schost
cs.SC