Almost work-optimal PRAM EREW decoders of LZ compressed text

Summary form only given. The parallel complexity of LZ compression and decompression has been studied. Parallel algorithms have been designed for LZ1 compression and decompression. LZ2 compression is hardly parallelizable, since it is P-complete. A nearly work-optimal parallel decoding algorithm was shown which run on the PRAM EREW in O(log n) time with O(n/(log n)¹2 /) processors for text compressed with LZ1 and LZ2 methods. Pseudo work-optimal PRAM EREW decoders for finite window compression and LZ2 compression requiring logarithmic time with O(dn) work are presented. Finally, the PRAM EREW decoders requiring logarithmic time and O(n/log n) processors were observed that are possible with the non-conservative assumption. The algorithms employed the Euler tour technique and parallel integer sorting.