LZMA


 * For the .lzma file format, see LZMA_Alone.

LZMA (Lempel–Ziv–Markov chain algorithm) is a general-purpose data compression algorithm and compressed data format. It's described as an advanced form of LZ77.

Specifications
No formal specification seems to exist, only source code. The Wikipedia article has some details about it (probably in violation of their rules about original research, so it might get removed). The Lzip manual also has some information about it.
 * Lzip Manual: Stream format

Software

 * LZMA SDK
 * XZ Utils → liblzma

Related formats

 * LZMA_Alone: Compressed file format that uses LZMA
 * Lzip: Compressed file format that uses LZMA
 * 7z: Compressed archive format that usually uses LZMA
 * LZMA2: An improved version of the data format (see also XZ)

Links

 * Wikipedia article