reserve p, q for Point of TOP-REAL 2,
  r for Real,
  h for non constant standard special_circular_sequence,
  g for FinSequence of TOP-REAL 2,
  f for non empty FinSequence of TOP-REAL 2,
  I, i1, i, j, k for Nat;

theorem
  1 <= i_w_n h & i_w_n h <= len GoB h & 1 <= i_e_n h & i_e_n h <= len
GoB h & 1 <= i_w_s h & i_w_s h <= len GoB h & 1 <= i_e_s h & i_e_s h <= len GoB
  h
proof
A1: [i_e_n h, width GoB h] in Indices GoB h by Def8;
A2: [i_w_s h, 1] in Indices GoB h by Def5;
A3: [i_e_s h, 1] in Indices GoB h by Def6;
  [i_w_n h, width GoB h] in Indices GoB h by Def7;
  hence thesis by A1,A2,A3,MATRIX_0:32;
end;
