1-In order to save storage space, the designer of a Boolean model information system decides to store only the first 4 letters of each word (as a form of truncation). Specify the effect this will have on precision and recall.

2-What is an inverted index used for? Build an inverted index for the following documents:

- D1= "Life is beautiful."

- D2= "Hello world."

- D3= "The world and life."

Calculate the array of suffixes, without auxiliary structure, of the string "Life is beautiful zzz Hello world zzz The world and life": use word suffixes, not character suffixes. Hint: your array should have less than 20 elements.

Compare Word Search by Suffix Array vs. Inverted Index: What's the Benefit of the Inverted Index?