some $x in E1 satisfies E2 returns true if there is an item in the
E1 for which the effective boolean value of
E2 is true.
E2 must use the range variable
$x to refer to the item being
tested; it does not become the context item. For example,
some $x in @* satisfies $x eq ""
is true if the context item is an element that has at least one zero-length attribute value.
Similarly, the expression
every $x in E1 satisfies E2 returns true if every item in the
sequence given by
E1 satisfies the condition.