Regular concatenation grammar
= Regular concatenation grammar
Retain every production $\alpha\to\beta$ of $P$ whose right-hand side contains a variable, replace every production $\alpha\to w$ with $w\in\Sigma^*$ by $\alpha\to wS'$, include $P'$, and use $S$ as start variable. If $G$ and $G'$ are right-linear, the resulting grammar is right-linear and generates $L(G)L(G')$.