Logico-semantic relation. There is a wide range of different logico-semantic relations any of which may hold between a primary and a secondary member of a clause complex. But it is possible to group these into a small number of general types, based on the two fundamental relationships of (1) EXPANSION and (2) PROJECTION. (1) Expansion: the secondary clause expands the primary clause, by (a) elaborating it, (b) extending it or (c) enhancing it.
- Halliday (1985), a pag.196