An example of Adjacency Filtering. The insight behind adjacency filtering: For a perfect mapping, all adjacent k-mers within a read should also be at adjacent locations within the reference. This is equivalent to searching for adjacent locations in adjacent k-mers' location lists.
Xin et al. BMC Genomics 2013 14(Suppl 1):S13 doi:10.1186/1471-2164-14-S1-S13