Found:

theta-grid

SYNTAX: the lexical specification of the thematic properties of a predicate. Originally (cf. Williams 1981b), a theta-grid is conceived of as an unordered list of theta-roles with only an indication of their status as being external (through underlining) or internal roles. More recently (cf. Grimshaw 1990), the theta-grid of a predicate is equated with its argument structure, which not only specifies an hierarchy among the theta-roles (through bracketing), but also their status as being a direct or indirect role, optional or obligatory, etc.

LIT.	Grimshaw, J. (1990) Roca, I. (1992) Williams, E. (1981b)