Found:

Function Chain

SYNTAX: the associated sequence of GFs of the members of the chain created by movement. EXAMPLE: in (i) John is assigned the function chain (GF1, GF2, GF3), where GF1 = [NP,IP1], GF2 = [NP, IP2] and GF3 = [NP,VP]. This entails that John is assigned the theta-role of the object of killed.

(i) [IP1 Johni was believed [IP2 ti to have been [VP killed ti]]]