\magnification=1200 \hsize=4in \overfullrule=0pt \input amssym %\def\frac#1 #2 {{#1\over #2}} \def\emph#1{{\it #1}} \def\em{\it} \nopagenumbers \noindent % % {\bf Edward A. Bender, E. Rodney Canfield and L. Bruce Richmond} % % \medskip \noindent % % {\bf Coefficients of Functional Compositions Often Grow Smoothly} % % \vskip 5mm \noindent % % % % The coefficients of a power series $A(x)$ are smooth if $a_{n-1}/a_n$ approaches a limit. If $A(x)=F(G(x))$ and $f_n^{1/n}$ approaches a limit, then the coefficients of $A(x)$ are often smooth. We use this to show that the coefficients of the exponential generating function for graphs embeddable on a given surface are smooth, settling a problem of McDiarmid. \bye .