Question

Given a wild-card query *led, 1) What Boolean query on a bigram index would be generated for this query? 2) There are many possible words for this query, given the possible words as following, which one is (a) true positive, (b) false positive, (c) won’t be returned: Words: 1. learned, 2. labeled, 3. legged, 4. lead.

Answer 1

The wild-card query *led can be represented as (??)led for a bigram index. The true positive is 'lead', the false positive is 'labeled', and 'legged' won't be returned.

Step-by-step explanation:

1) A wild-card query *led represents a query where the first part of the word is unknown, and the last three letters are 'led'. For a bigram index, the generated Boolean query would be (??)led, where the question marks represent the unknown characters at the beginning of the word.

2) Based on the given possible words: 1. learned, 2. labeled, 3. legged, 4. lead. (a) The true positive would be 'lead' as it matches the given query form '*led'. (b) The false positive would be 'labeled' as it doesn't match the query form '*led'. (c) The word 'legged' won't be returned as it doesn't match the query form '*led' either.