A I<property> is a I<name=value> pair.
A I<property definition> is a sequence of comma separated properties.
-There can be any number of properties in a definition.
+There can be any number of properties in a definition, however each name must
+be unique.
For example: "" defines an empty property definition (i.e., no restriction);
"my.foo=bar" defines a property named I<my.foo> which has a string value I<bar>
and "iteration.count=3" defines a property named I<iteration.count> which
match counts in favor of the algorithm.
More details about that in the B<Lookups> section.
A I<property query> is a sequence of comma separated property query clauses.
+It is an error if a property name appears in more than one query clause.
The full syntax for property queries appears below, but the available syntactic
features are: