theorem Lem11: :: MSAFREE5:135

for S being non empty non void ManySortedSign
for s being SortSymbol of S
for X being non-empty ManySortedSet of the carrier of S
for x being Element of X . s
for t, t1 being Element of (Free (S,X))
for xi being Element of dom t st t . xi = [x,s] holds
dom t c= dom (t with-replacement (xi,t1))