Formal approaches to the design of interactive systems, such as the principled design approach rely on reasoning about properties of the system at a v ery high level of abstraction. Such specifications typically provide little scope for reasoning about presentations and the representation of information in the pres entation. Theories of distributed cognition place a strong emphasis on the role of representations in the cognitive process, but it is not clear how such theories ca n be applied to design.
In this paper we show how a formalisation can be used to encapsulate representational aspects, affording us an opportunity to int egrate representational reasoning into the design process. We have shown in [3] how properties over the abstract state place requirements on the presentation if the properties are to be valid at the perceptual level, and we have presented a model for such properties. We base our approach on this model, and examine in more detail the issue of verification. Given the widespread consensus that proper tool support is a prerequisite for the adoption of formal techniques, we apply a higher-order logic theorem prover to the analysis.

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