A simple example of eliminating single variables on the rhs. Original grammar: S -> A S -> AB S -> aSb A -> a A -> C A -> aA C -> CBa C -> ba B -> b Replacement grammar: S -> a S -> CBa S -> ba S -> aA S -> AB S -> aSb A -> a A -> CBa A -> ba A -> aA C -> CBa B -> b A simple example of eliminating rhs's with more than 2 symbols: Original grammar: S -> ASB S -> ab A -> a B -> b B -> bSSa Replacement grammar: S -> DB D -> SB S -> ab A -> a B -> b B -> Ea E -> FS F -> bS