Term Vocabulary and Postings Lists Vocabulary of Terms Numbers 3/20/91 Mar12,1991 20/391 55B.C B-52 My PG key is 324a3df234cb23e 800)234-2333 Often have embedded spaces Older iR systems may not index numbers But often very useful: think about things like looking up error codes/stacktraces on the web (One answer is using n-grams Lecture 2.2) Will often index"meta-data" separately Creation date, format etcTerm Vocabulary and Postings Lists 10 Numbers ▪ 3/20/91 Mar. 12, 1991 20/3/91 ▪ 55 B.C. ▪ B-52 ▪ My PGP key is 324a3df234cb23e ▪ (800) 234-2333 ▪ Often have embedded spaces ▪ Older IR systems may not index numbers ▪ But often very useful: think about things like looking up error codes/stacktraces on the web ▪ (One answer is using n-grams: Lecture 2.2) ▪ Will often index “meta-data” separately ▪ Creation date, format, etc. Vocabulary of Terms