Question: Questions about elementwise equal =~ and replacing names by functions

I was about to use a compact piece of code (subs(x =~ x(t), [d])) that makes names xi in an expression d functions of t (where i is a nonnegative integer); i.e. :
   xi -> xi(t)

The code works inside a procedure but not when passed as Maple input (see attachment).

What is the reason that it works at all?  Can my current way of replacing names by functions be improved?

Please Wait...