Note that the symbols sent over the channel are not binary. For a binary channel the symbols (e.g. integers \{ 1,\ldots ,9 \}) have to be mapped onto base 2. The binary erasure channel model however is not applicable because it erases only individual bits with some probability and not Sudoku symbols. If the symbols of the Sudoku are sent in packets the channel can be described as a packet erasure channel model.
