[...] most current theories of syntax (e.g. Marantz [Marantz, A., 1981, ‘On the Nature of Grammatical Relations’, MIT Cambridge], Chomsky [Chomsky, N., 1981, Lectures on Government and Binding, Foris, Dordrecht]) allow only obligatory arguments to be represented in lexical argument structures (what RS call subcategorization frames).
- Lieber (2004), a pag.242

RS's subcategorization frames are comparable to what I have been calling "argument structures" - that is, they indicate the NPs, As and PPs with which a verb must (or can) be associated in order to form a grammatical sentence.
- Lieber (2004), a pag.246