I have realized that the counts with this function 'subs' doing x(1) +1*x(2) and x(1) + 1*x(2) are differents, for example. The space in these expressions give me results differents.
Which the problem?
Which is correct? I think that the correct is x(1) +1*x(2) and not with the space.
No products are associated with this question.
In the context of the  operation,
would usually be interpreted as
which is two entries.
x(1) + 1*x(2)
inside  would be interpreted as one entry.
If you are not within the context of  then the two should be the same.