reserve I for set;
reserve S for non empty non void ManySortedSign,
  U0, U1 for non-empty MSAlgebra over S;
reserve s for SortSymbol of S;
reserve e for Element of (Equations S).s;
reserve E for EqualSet of S;

theorem
  for U2 being strict non-empty MSSubAlgebra of U0 st U0 |= E holds U2 |= E
by Th31;
