Consider the following fragment of a positional index with the format: word: document: {position, position, . . .}; document: {position, . . .} Gates: 1: {3}; 2: {6}; 3: {2,17}; 4: {1}; IBM: 4: {3}; 7: {14}; Microsoft: 1: {1}; 2: {1,21}; 3: {3}; 5: {16,22,51};

The /k operator, word1 /k word2 finds occurrences of word1 within k words of word2 (on either side), where k is a positive integer argument. Thus k = 1 demands that word1 be adjacent to word2.

Question (Describe each set of values for k for which the query Gates /k Microsoft returns a different set of documents as the answer.)