2.1.4 Notations for environments

"This document uses environment groups that group related environments."
    I think you'd be better off if you changed your terminology somewhat:
    Instead of saying:
        statEnv and dynEnv are "environment groups"
        whose members are "environments",
    say:
        statEnv and dynEnv are "environments",
        (some of) whose members are "mappings" ["dictionaries"]
    Note that after section 3 (and sometimes even within it), statEnv and
    dynEnv *are* generally referred to as "environments". Also note that
    it's "statEnv" and "dynEnv", not "statEnvGroup" and "dynEnvGroup".
(leftover from last year, comment #019)

"which models to the [XPath/XQuery]'s dynamic context"
    Delete "to".

"Environment groups can be updated, using the following notation:"
    The list omits the notation for updating via a non-mapping component
    (as used in 4.9, 5.4, etc).

"the expression$x - 3."
    Insert space before '$'.