Dependent vs Embedded Prepositional Phrases

Martin, Matthiessen & Painter (2010: 200):

Given this situation, it may not be obvious why the prepositional phrase is not regarded as an embedded Qualifier. The difference is that a phrase linked to a nominal group within a complex does not define the nominal group. For this reason it can be used with a proper name; and there is a contrast in meaning between (a) [α:] Margaret, [β:] in a yellow raincoat, greeted us and (b) the woman [in a yellow raincoat] greeted us. In (a), the referent of the nominal group has already been established and Margaret is sufficient to identify her. In contrast, in (b), the prepositional phrase in a yellow raincoat is needed to define the referent of the nominal group of which it is part. 

Blogger Comments:

[1] This is potentially misleading. On the one hand, a non-defining prepositional phrase can also elaborate nominal groups without a proper name, as exemplified by the woman, in a yellow raincoat, greeted us, where the sense is 'who was incidentally wearing a yellow raincoat':

On the other hand, a defining prepositional phrase can also qualify a proper name in a nominal group, as exemplified by the Margaret in a yellow raincoat greeted us, where the sense is 'not the Margaret in a red raincoat':

[2] To be clear, the distinction here is simply between 'non-defining' and 'defining'. In (a), the prepositional phrase is agnate to a non-defining relative clause, whereas in (b), it is agnate to a defining relative clause. A non-defining relative clause serves as an elaborating unit in a complex, whereas a defining relative clause serves as the Qualifier of a nominal group. Halliday & Matthiessen (2014: 561):

It is important to distinguish between an elaborating group and an embedded group occurring as Qualifier: e.g. (taxis, elaborating) his latest book, ‘The Jaws of Life’, (embedded) his book ‘The Jaws of Life’. The former is related to a non-defining relative; it means ‘his latest book – which is “The Jaws of Life” ’, and is marked by tone concord:

//4 ^ his /latest /book the //4 jaws of /life was a //1 ghastly suc/cess //

The latter is related to a defining relative clause; it means ‘this particular book of his (he has written others)’ and has no tonic prominence on book.

[3] The use of 'referent' here is misleading. Importantly, in SFL Theory, nominal groups do not refer; they realise semantic elements, such as participants. It is reference items that refer, and a nominal group is not a referent unless it is referred to by a reference item elsewhere in a text.