Partial Timeline of Progress
- 1949 Superimposed coding
- 1957 Hashing -- open addressing
- 1957 Term weighting
- 1960 Tries; Cranfield experiments
- 1968 Patricia trees; Lovins stemmer
- 1972 B-trees
- 1975 Lex
- 1976 Probabilistic feedback
- 1977 Fast string matching
- 1980 Hashing -- dynamic
- 1987 PAT arrays