The deletion approach is a standard one in compression research, although the problem is often formulated over the syntactic structure and not the raw token sequence.
one usually drops constituents or prunes dependency edges (Jing, 2000;Knight & Marcu, 2000;McDonald, 2006;Clarke & Lapata, 2008;Berg-Kirkpatrick et al., 2011;Filippova & Altun, 2013).