It seems that 'output' can be used in the form 'output(...)' or
'output ...'. For example, 'output(i)' but 'output [x,y]' in the Axiom
book. What is the difference and where is this actually documented?
I've hunted in HyperDoc, in the Axiom book and in Martin Dunstan's
tutorial without success.
(I'm still working on digesting the responses to my previous
questions.)