![](https://moodlearchive.epfl.ch/2022-2023/pluginfile.php/1659600/mod_forum/post/162250/image.png)
![](https://moodlearchive.epfl.ch/2022-2023/pluginfile.php/1659600/mod_forum/post/162250/image%20%281%29.png)
Is it necessary to introduce the new rules X, Y, Z, U? Or could we also simplify the rules as such:
S -> S PNP
S -> S NP
VP -> VP PNP
NP -> NP Adj
since S -> NP VP, VP -> V NP, NP -> Det AN are already defined? Or is there another reason that we create the extra rules that I'm not understanding?