Use of Disjunction in XPath

Dear all,

I have a question about the use of disjunction in XPath:

Is it possible to write path expressions like the following one?

a / ( a|  b) / (c | d/g)

After looking at the grammar of XPath, it seems to me that
this is not possible, as a disjunctive normal form is required.
Obviously, if this is true, the above expression MUST be written
in the form:

(a/a/c) | (a/a/d/g) | (a/b/c) | (a/b/d/g)

Best wishes

Filippo Furfaro