[rules = sets].
'Rules: sets.                    Location: SPADE$CHECKER:SETS.RUL'.
''.
'A family of rules for the FDL set operators.  The main groupings are:'.
''.
'    (1-3):  simple  X in A  &  X not_in A  rules.'.
'   (4-11):  properties of set union (\\/).'.
'  (12-19):  properties of set intersection (/\\).'.
'  (20-27):  properties of set "lacking" (\\).'.
'     (28):  X not_in (set []): nothing is in the empty set.'.
'  (29-36):  properties of the subset_of relation.'.
'     (37):  definition of strict_subset_of relation.'.
'  (38-39):  commutativity of \\/ and /\\.'.
'  (40-41):  associativity of \\/ and /\\.'.
'  (42-43):  distributivity of /\\ over \\/ and \\/ over /\\.'.
