>\text{parse-from}_G(\sigma_2\ldots\sigma_n, P') &amp; \text{if } \boldsymbol\sigma = \sigma_1\sigma_2\ldots\sigma_n <span class="sc">\\</span></span>
<span id="cb1-39"><a href="#cb1-39" aria-hidden="true" tabindex="-1"></a>\emptyset &amp; \text{otherwise}</span>
<span id="cb1-40"><a href="#cb1-40" aria-hidden="true" tabindex="-1"></a>\end{cases}</span>
<span id="cb1-41"><a href="#cb1-41" aria-hidden="true" tabindex="-1"></a>$$</span>
<span id="cb1-42"><a href="#cb1-42" aria-hidden="true" tabindex="-1"></a>