Literal shuffle of compressed words

Abstract

Straight-Line Programs (SLP) are widely used compressed representations of words. In this work we study the rational transformations and the literal shuffle of words compressed via SLP, proving that the first preserves the compression rate, while the second does not. As a consequence, we prove a tight bound for the descriptional complexity of 2D texts compressed via SLP. Finally, we observe that the Pattern Matching Problem for texts expressed by the literal shuffle of compressed words is NP-complete. However, we present a parameter-tractable algorithm for this problem, working in polynomial time whenever the length of the pattern is polynomially related to that of the text. © 2008 Springer Science+Business Media, LLC.