theorem :: EXTENS_1:18

for S being non empty non void ManySortedSign
for U1 being MSAlgebra over S
for U2 being MSSubAlgebra of U1
for B1 being MSSubset of U1
for B2 being MSSubset of U2 st B1 = B2 holds
GenMSAlg B1 = GenMSAlg B2