A Formalisation of the Normal Forms of Context-Free Grammars in HOL4 [chapter]

Aditi Barthwal, Michael Norrish
2010 Lecture Notes in Computer Science  
We describe the formalisation of the Chomsky and Greibach normal forms for context-free grammars (CFGs) using the HOL4 theorem prover. We discuss the varying degrees to which proofs that are straightforward on pen and paper, turn out to be much harder to mechanise. While both proofs are of similar length in their informal presentations, the mechanised proofs for Greibach normal form blow-up considerably.
doi:10.1007/978-3-642-15205-4_11 fatcat:bctvnjpsnbbbfcuvht2vylnorq