reserve S for non void non empty ManySortedSign,
  U0 for MSAlgebra over S;
reserve S for non void non empty ManySortedSign,
  X for ManySortedSet of the carrier of S,
  o for OperSymbol of S,
  b for Element of ([:the carrier' of S,{the
  carrier of S}:] \/ Union (coprod X))*;
reserve x for set;

theorem Th17:
  for S be non void non empty ManySortedSign, X be non-empty
  ManySortedSet of the carrier of S holds FreeMSA(X) is free
proof
  let S be non void non empty ManySortedSign, X be non-empty ManySortedSet of
  the carrier of S;
  take FreeGen(X);
  thus thesis by Th16;
end;
