This means that pure B&K-CCG is just as unable to generate L 3 as pure CCG is.
the weak generative capacity of CCG with rule restrictions, and in particular that of the formalism considered by Vijay-Shanker and Weir (1994), is strictly greater than the generative capacity of pure B&K-CCG-although we conjecture (but cannot prove) that pure B&K-CCG is still more expressive than pure non-modal CCG.