Nondeterministic variants of LR(k) parsing, for use in natural language processing, have been proposed as well, some using tabulation to ensure polynomial running time in the length of the input string (Tomita, 1988;Billot and Lang, 1989).
nondeterministic LR(k) parsing is potentially as expensive as, and possibly more expensive than, traditional tabular parsing algorithms such as CKY parsing (Younger, 1967;Aho and Ullman, 1972), as shown by for example (Shann, 1991); greater values of k make matters worse (Lankhorst, 1991).