theorem Th6: :: MSAFREE:6

for S being non empty non void ManySortedSign
for X being ManySortedSet of the carrier of S holds
( NonTerminals (DTConMSA X) c= [: the carrier' of S,{ the carrier of S}:] & Union (coprod X) c= Terminals (DTConMSA X) & ( X is non-empty implies ( NonTerminals (DTConMSA X) = [: the carrier' of S,{ the carrier of S}:] & Terminals (DTConMSA X) = Union (coprod X) ) ) )