theorem Th73:
  for S being (11,1,1)-array 11 array-correct bool-correct non empty non void
  BoolSignature
  for I being integer SortSymbol of S holds
  the_array_sort_of S <> I &
  (the connectives of S).11 is_of_type <*the_array_sort_of S,I*>, I &
  (the connectives of S).(11+1) is_of_type <*the_array_sort_of S,I,I*>,
  the_array_sort_of S &
  (the connectives of S).(11+2) is_of_type <*the_array_sort_of S*>, I &
  (the connectives of S).(11+3) is_of_type <*I,I*>, the_array_sort_of S
  proof
    let S be (11,1,1)-array 11 array-correct bool-correct non empty
    non void BoolSignature;
    let I be integer SortSymbol of S;
    consider J,K,L being Element of S such that
A1: L = 1 & K = 1 & J <> L & J <> K &
    (the connectives of S).11 is_of_type <*J,K*>, L &
    (the connectives of S).(11+1) is_of_type <*J,K,L*>, J &
    (the connectives of S).(11+2) is_of_type <*J*>, K &
    (the connectives of S).(11+3) is_of_type <*K,L*>, J by AOFA_A00:def 51;
    the_array_sort_of S = J & I = 1 by A1,AOFA_A00:def 40;
    hence thesis by A1;
  end;
