Halliday & Matthiessen (1999: 58-9):
As we have seen, elements fill the roles of figures. Participant roles are filled by participants (things or qualities), circumstance roles by circumstances (times, places, causes, etc.), and the process role by a process. There are correlations here between the taxonomy of configurational phenomena and that of simple phenomena … .
The elements of a figure are of three kinds:
(i) the process itself (action/event, process of consciousness, or relation),
(ii) a participant in that process, or
(iii) a circumstantial element or circumstance. …
As already noted above, processes are realised by verbal groups, participants by nominal groups, and circumstances by adverbial groups or prepositional phrases. In addition to the three types of element that serve in figures, there is one further type of element — the relator: see Plate 4. Relators serve to construe logico-semantic relations of expansion between figures in a sequence; they are realised by conjunction groups.
