Several parsers have been implemented in various grammar formalisms and empirical evaluation has been reported: LFG (Riezler et al., 2002;Cahill et al., 2002;Burke et al., 2004), LTAG (Chiang, 2000), CCG (Hockenmaier and Steedman, 2002b;Clark et al., 2002;Hockenmaier, 2003), and HPSG (Miyao et al., 2003;Malouf and van Noord, 2004).
their accuracy was still below the state-of-theart PCFG parsers (Collins, 1999;Charniak, 2000) in terms of the PARSEVAL score.