the algorithm published by p>Ziv and Lempel in 1977 was later called LZ77 algorithm.
in p>1978, they published a sequel named LZ78 compression algorithm.
in p>1984, Welch studied the variant of LZ78 algorithm, which was called LZW algorithm because it was developed by W after Z and L..
LZW applied for a patent, but the patent expired in 23.
almost all compression algorithms are developed from LZ77.
The so-called LZ77 coding and LZW coding are new codes generated by compressing the original character sequence with their own compression algorithms.