-provides the ability to select all messages not elements of a
-user-defined sequence. To do this, the user should define the entry
-\*(lqSequence\-Negation\*(rq in the
+provides the ability to select all messages
+.B not
+elements of a user-defined sequence.
+A special string is used to preface an existing user-defined
+sequence name. This specification then refers to those
+messages not elements of the specified sequence name.
+The default negation prefix is the exlamation mark `!',
+but it may be change to any string, by defining the entry
+`Sequence\-Negation' in the