# Is there an algorithm for converting a CFG in Greibach Normal Form into a CFG in strong GNF?

A CFG is in strong GNF when all rewrite rules are in the following form:

$A \rightarrow aA_1...A_n$

where $n \leq 2$.

• What are your thoughts? Have you tried coming up with such an algorithm? Have you tried searching the net for such an algorithm? – Yuval Filmus Nov 27 '16 at 8:33
• I had already constructed the algorithm for converting a CNF CFG into a GNF CFG. From there I thought it'd be easier to convert a GNF CFG into a SGNF CFG but I have yet to find a way. I had looked around but it appears strong GNF is not a widely used term. – user393454 Nov 27 '16 at 8:51