reserve S for non void non empty ManySortedSign,
  V for non-empty ManySortedSet of the carrier of S;
reserve A for MSAlgebra over S,
  t for Term of S,V;

theorem
  for A being non-empty MSAlgebra over S for s being SortSymbol of S, x
  being Element of (the Sorts of A).s holds the_sort_of (x-term (A,V)) = s by
