Defeasible logic is a nonmonotonic language that allows new inferences to be made as new information is discovered. It was developed in order to be efficiently and easily implemented. However, in order to be more widely applicable the addition of expressing time has been highlighted. This allows a defeasible theorem to reason over statements that may have been true in the past but may not be true in present or in the future.
In order to add this extra dimension, a defeasible logic system has been developed and the additional functionality added. An architecture has been developed that allows the expression of temporal rules and literals and for the system to be able to reason over these rules.
The efficiency of the implemented defeasible logic system and its temporal counterpart is investigated. This includes the effect of the developed architecture on the time and resources required to reason over these temporal theorems.
To help implement this system and to allow end users to create theorems a mini-language, or domain specific language, has also been developed. This provides a restricted but powerful set of commands to be used in order to create defeasible and temporal defeasible logic theorems.