Higher CompressionfromtheBurrows-Wheeler Transformby ModiedSorting

We show that the ordering used in the sorting stage of the Burrows-Wheeler transform, an aspect hitherto ignored, can have a signicant impact on the size of the compressed data. We presentexperimentalresultsshowingsmallercompressedoutputachievedwithtwomodications to the sorting: using a better alphabet ordering and reflecting the sorted strings as in binary reflected Gray coding.