reserve i for object;
reserve S for non empty ManySortedSign;
reserve D for non empty set,
  n for Nat;

theorem Th7:
  for MS being segmental non void 1-element ManySortedSign
, i being OperSymbol of MS, A being non-empty MSAlgebra over MS holds Args(i,A)
  c= (the_sort_of A)*
proof
  let MS be segmental non void 1-element ManySortedSign, i be
  OperSymbol of MS, A be non-empty MSAlgebra over MS;
  Args(i,A) = (len the_arity_of i)-tuples_on the_sort_of A by Th6;
  hence thesis by FINSEQ_2:142;
end;
