XML schema draft comments: is list canonical form underspecified?

Regarding the draft at
http://www.w3.org/TR/2004/PER-xmlschema-2-20040318/:

Section 2.5.1.2 says:

    The canonical-lexical-representation for the ·list· datatype is
    defined as the lexical form in which each item in the ·list· has
    the canonical lexical representation of its ·itemType·.

Is that canonical form underspecified?  Specifically, doesn't
it need to specify canonical form of space-separating the list
of item lexical values?

_If_ "a b" and "a  b" (two spaces) are both legal lexical values,
which is the canonical lexical representation?



Daniel