(4) proposition= π3 Xi:[[extended predication]( σ3)n](Xi) The “proposition” consists of a propositional content variable Xi, symbolizing a possible fact PF, specified by the extended predication, propositional (or: “attitudinal”) operators π3, and Level-3 satellites σ3. These level-3 elements serve to specify the speaker’s evaluation of and commitment to the PF defined by the proposition.
- Dik (1989), a pag.247-248

We can now say that a predication, which designates an SoA [state of affairs], can be built into a higher-order structure: “the proposition”, which designates a “propositional content” or a “possible fact”.
- Dik (1989), a pag.48