Practical Grammar 7

Prepositional Phrases: explaing the complex annotation

The textbook contains a c-structure rule for VP like the following:

1. VP → V          PP
       ↑=↓   (↑ (↓ PCASE)) = ↓

which translates into the following xlfg rule:

1. VP → V PP
2. {
3. ↑=↓1;
4. (↑ (↓2 PCASE)) = ↓2;
5. }

In the following, I will explain the annotation (↑ (↓ PCASE)) = ↓ on the PP.

(↑ SUBJ) =↓1;

1. S -> NP VP
2. {
3.  (↑ SUBJ) =↓1;
4.  ↑=↓2;
5. }