A Supernormal-Form Theorem for Context-Free Grammars
Hermann A. Maurer, A. Salomaa, D. Wood · Journal of the ACM · 1983
For every triple (k, /, m) of nonnegaUve integers, every context-free grammar G can be transformed rote a normal form where (1) each nontermmating production is of the type A ~ wkBwtCw,~ with I wk [ = k, I wll --/, and I w,~ [ = m, and 00 each terminating producUon A ~ w has the property that I wl appears m the length set of L(G).Apphcations and generalizations of this result are discussed.