= n_0$, and

2.  all daughters of $v$ are leaves, which are labeled with $l_1 \ldots l_i$, and

3.  $\phi[x_0/n_0]$ is in the set $F$.

An internal node $v$ of an annotated constituent structure tree is [*licensed*]{} by a syntactic rule $(c_0, l_1,\ldots,l_i, c_1,\phi)$ iff

1.  the node $v$ is labeled with category $c_0$, $h(v) = n_0$, and

2.  one of $v$’s daughters is an internal node, $v_1$, which is labeled with category $c_1$, and $h(v_1) = n_1$, and

3.  the daughters of $v$ that are leaves are labeled with $l_1 \ldots l_i$, and

4.  $\phi[x_0/n_0, x_1/n_1]$ is in the set $F$.

Weak Generative Capacity {#WGC}
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In [@lp-95-01], it is shown that the recognition problem for R-AVGs is ${\mathord{\it NP}}$-complete. This seems to indicate that although the mechanism for generating CSTs in R-AVGs is extremely simple, the generative capacity of R-AVGs is different from the generative capacity of e.g., context free languages (CFLs), which have a polynomial time parsing algorithm [@earley:70]. Yet, a priori, there may exist CFLs that do not have an R-AVG.

\[ravgl\] Let $L$ be a context free language. There exists an R-AVG $G$ such that $L=L(G)$.

If $L$ is a context free language, then there 