Although the project was already underway, the most active research occurred for the submission of a response to the OMG's MOF 2.0 Queries / Views / Transformations Request for Proposals.
These elements are based on F-logic and pure logic programming, however the absence of function symbols means a significant reduction in complexity.
Thus injections are similar (but more powerful) to QVT's keys, which specify a target object's identity to be a function of its type and some of its properties.
The declarative semantics of a Tefkat transformation is the perfect model of traces and targets that satisfies all the rules.
Tefkat has an SQL-like concrete syntax designed to concisely convey the intent of each rule, pattern or template.