Without changing the source code to ratexpand, I don't think it's possible
to
get things like ratexpand(pochhammer(x,10)) to expand; nevertheless, I
think
my proposed simplification rules for pochhammer are an improvement:
(%i10) pochhammer(x,10);
(%o10) pochhammer(x,10)
(%i11) expand(%);
(%o11) x^10+45*x^9+870*x^8+9450*x^7+63273*x^6+269325*x^5+723680*x^4
+1172700*x^3+1026576*x^2+362880*x
Uses numeric.lisp:
(%i12) pochhammer(2/3 + %i, 10);
(%o12) (6692741900*%i)/19683-180075197900/59049
(%i20) pochhammer(1.042b0 + %i, 200);
(%o20) 1.404291479851284b375-1.244250112853149b375*%i
(%i21) pochhammer(13/2, 7/2);
(%o21) 24576/(11*sqrt(%pi))
(%i22) pochhammer(x,-n);
(%o22) 1/pochhammer(x-n,n)
(%i23) subst(n=-10,%);
(%o23) pochhammer(x,10)
Barton