The class of translations yield(MBOT) is equivalent to yield(1-m-LCFRS), where 1-m-LCFRS is defined to be the class of LCFRS grammars where each rule either is a start rule of the form S → g(S i ), g( e, f ) = e#f , or meets both of the following conditions: r The combination function keeps the two sides of the translation separate.
it must be possible to write where + represents tuple concatenation, for some functions g 1 and g 2 .