10. The computer program product of claim 9 , wherein the term index includes a posting list for each term used in the plurality of documents, wherein the plurality of documents further includes: (i) a first document having, inside the specified context, an occurrence of the first search term and no occurrences of the second search term and, outside the specified context, an occurrence of the second search term and no occurrences of the first search term (ii) a second document having, inside the specified context, respective occurrences of the first and second search terms and, outside the specified context, no occurrences of any of the first and second search terms.
11. The computer program product of claim 10 , wherein the plurality of documents further includes: (iii) a third document having, inside the specified context, respective occurrences of the first and second search terms and, outside the specified context, an occurrence of the first search term and no occurrences of the second search term; (iv) a fourth document having, inside the specified context, an occurrence of the first search term and no occurrences of the second search term and, outside the specified context, respective occurrences of the first and second search terms.