MLT – Multi-Level Theory

This is a resources page for the MLT Multi-Level Theory. MLT formally characterizes the nature of classification levels, and precisely defines the relations that may occur between elements of different classification levels, generalizing the notion of power type.

Original paper describing MLT: carvalho-almeida-sosym-final revision (published at ttp://

MLT Repository on Github with formal specification in Alloy:

MLT Repository on Github with OWL ontology reflecting MLT rules: