prd_atomSent :: ATOM -> Set.Set NAME
prd_atomSent a =
    case a of
         Equation t1 t2 -> unifyPredicates prd_term [t1,t2]
         Atom t tseq ->
            if null tseq
               then prd_term t
               else Set.union (prd_termSeqs tseq) $ prd_add_term t
prd_atomSent :: ATOM -> Set.Set NAME
prd_atomSent a =
    case a of
         Equation t1 t2 -> unifyPredicates prd_term [t1,t2]
         Atom t tseq ->
            if null tseq
               then prd_term t
               else Set.union (prd_termSeqs tseq) $ prd_add_term t
prd_atomSent a =
    case a of
         Equation t1 t2 -> unifyPredicates prd_term [t1,t2]
         Atom t tseq ->
            if null tseq
               then prd_term t
               else Set.union (prd_termSeqs tseq) $ prd_add_term t