Here we consider the extended top-down tree transducer (XTOP), which was studied in (Arnold and Dauchet, 1982;Knight, 2007;Graehl et al., 2008;Graehl et al., 2009) and implemented in the toolkit TIBURON (May and Knight, 2006;May, 2010).
we investigate compositions of linear and nondeleting XTOPs (ln-XTOP).