The Maxima help manual states that
dependencies is a list of atoms which have a
functional dependence, assigned by depends or
gradef.
The help manual omits that dependencies is
also a function:
(%i1) dependencies;
(%o1) []
(%i2) depends(u,t);
(%o2) [u(t)]
(%i3) dependencies;
(%o3) [u(t)]
(%i4) dependencies(a(t));
(%o4) [a(t)]
(%i5) dependencies;
(%o5) [u(t), a(t)]
Ted Woollett