Regular grammars, covers, Greibach normal form

Each context-free grammar can be transformed to a context-free grammar in Greibach normal form, that is, a con text-free grammar where each right-hand side of a prorfuction begins with a terminal symbol and the remainder of the right-hand side consists of nonterminal symbols. In this short paper we show that for a left-regular grammar G we can obtain a right-regular grammar G’ (which is by definition in Greibach normal form) which left-to-right covers G (in this case left parses of G ’ can be mapped by a homomorphism on right parses of G. Moreover, it is possible to obtain a context-free grammar G ” in Greibach normal form which right covers the left-regular grammar G (in this case righ