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 Th36:
  1 <= i & i <= len GoB h & 1 <= j & j <= width GoB h implies ex q
  st q`2 = (GoB h)*(i,j)`2 & q in L~h
proof
  assume that
A1: 1 <= i and
A2: i <= len GoB h and
A3: 1 <= j and
A4: j <= width GoB h;
  consider k such that
A5: k in dom h and
  [i,j] in Indices GoB h and
A6: (h/.k)`2 = (GoB h)*(i,j)`2 by A1,A2,A3,A4,Th10;
  take q = h/.k;
  thus q`2 = (GoB h)*(i,j)`2 by A6;
  4 < len h by GOBOARD7:34;
  hence thesis by A5,GOBOARD1:1,XXREAL_0:2;
end;
