theorem Th20: :: RADIX_3:20

for n, m, k, i being Nat st i in Seg n & 2 <= k holds
DigA_SDSub ((SD2SDSub (DecSD (m,(n + 1),k))),i) = DigA_SDSub ((SD2SDSub (DecSD ((m mod ((Radix k) |^ n)),n,k))),i)