A Bijective String Sorting Transform

TL;DR

This paper introduces a bijective variant of the Burrows-Wheeler Transform that achieves comparable or better compression ratios, with linear time and space complexity, and guarantees invertibility for all strings.

Contribution

A novel bijective string sorting transform that improves upon the original BWT in compression performance while ensuring invertibility and linear computational complexity.

Findings

Achieves better compression ratios than the original BWT.

Can be computed and inverted in linear time and space.

Ensures invertibility for all input strings.

Abstract

Given a string of characters, the Burrows-Wheeler Transform rearranges the characters in it so as to produce another string of the same length which is more amenable to compression techniques such as move to front, run-length encoding, and entropy encoders. We present a variant of the transform which gives rise to similar or better compression value, but, unlike the original, the transform we present is bijective, in that the inverse transformation exists for all strings. Our experiments indicate that using our variant of the transform gives rise to better compression ratio than the original Burrows-Wheeler transform. We also show that both the transform and its inverse can be computed in linear time and consuming linear storage.