Thoughts on Information Retrieval, Search Engines, Data Mining, Science, Engineering, and Programming source: http://www.cs.princeton.edu/~blei/papers/BleiNgJordan2003.pdf There is a kind of buzz about Probabilistic Latent Semantics Indexing, so this post goes. From VSM to LSI Prior to 1988 the prevalent IR model was Salton’s Vector Space Model (VSM). This model treats documents and queries as vec