Canonical Derivations in Programmed Grammars

This work studies canonical derivations (with focus on leftmost derivations) in programmed grammars and left restriction range. It is shown that if we introduce n-limited derivations in programmed grammars as they were defined for state grammars, we get an infinite hierarchy of language families resulting from n-limited programmed grammars, so the left restriction range affects the generative power of n-limited programmed grammars. This result is significant for syntactical analysis based on programmed grammars