User:Kinematografia/sandbox

My name is GYORGY REVESZ. This is an addition to the article about "Kuroda Normal Form" whic cites one of my papers. Gyorgy Revesz.

Actually, the papessr by Gyorgy Revesz provides another normal form where only one sided (say, left-sided) context sensitive rules are needed in addition to the order-reversig (flipping) rules like AB -> BA. Therefore,  to every 'noncontracting' grammar there exists a weakly equivqlent grammar whose rules are all of the form AB -> BA or AB -> AC or A ->  BC or A  -> B   or A  ->  a Namely, right-sensitive rules like  AB -> CB  can be replaced by the following rules: AB -> AB' 	  A -> A' A'B' -> A'D   A'  -> E ED   ->  DE	    D  -> C' C'E  ->  C'E'	C'  -> C CE'  ->  C B For unrestricted phrase structure grammers we need to add only one more type of rules, AB -> B.  More details can be found in the book Introduction to Formal Languages by Gyorgy Revesz.