CFGs: Derivations and Ambiguity
Context-free grammars as 4-tuples, derivations, sentential forms and yields, the one-to-one link between parse trees and leftmost derivations, ambiguous grammars and how to show ambiguity, standard ambiguous grammars and their unambiguous rewrites (precedence, associativity, dangling else), inherent ambiguity, the grammar-to-language table for standard grammars, and the solved 2026 question on counting derivations. Every language and parse-tree count was computed by script.
