for i, m, n being Nat
for D being compact non horizontal non vertical Subset of (TOP-REAL 2)
for k being Nat st 2 <= m & m + 1 < len (Gauge (D,i)) & 2 <= n & n + 1 < len (Gauge (D,i)) holds
cell ((Gauge (D,i)),m,n) = union { (cell ((Gauge (D,(i + k))),a,b)) where a, b is Nat : ( (((2 |^ k) * m) - (2 |^ (k + 1))) + 2 <= a & a <= (((2 |^ k) * m) - (2 |^ k)) + 1 & (((2 |^ k) * n) - (2 |^ (k + 1))) + 2 <= b & b <= (((2 |^ k) * n) - (2 |^ k)) + 1 ) }