On the (non-) relationship between SLR(1) and NQLALR(1) grammars
Manuel E. Bermudez, Karl M. Schimpf · ACM Transactions on Programming Languages and Systems · 1988
A popular but “not-quite” correct technique for computing LALR(1) look-ahead sets has been formalized by DeRemer and Pennello and dubbed NQLALR(l). They also claim that the class of SLR(l) grammars is a subset of the class of NQLALR(1) grammars. We prove here that no such relationship exists between those two classes. We do so with a counterexample that, ironically, appeared in DeRemer and Pennello's own paper.