Caution
	The Cognitive Tutor (TDK) tutor type is not supported in this version of CTAT.

A Cognitive Tutor (TDK) is a tutor based on the TDK (Tutor Development Kit) production rule language. This tutor type requires access to a LISP rule engine, which is not included with CTAT.

The TDK modeling language was used to develop the Algebra and Geometry Cognitive Tutors.