Abstract: The invention relates to service delivery, for example, in the context of mobile user interface devices. In particular, the invention describes methods for matching structured descriptions where the structured descriptions specify aspects or attributes of the requestor and/or the requestors' environment or context as well as the available services. The process includes the steps of detecting a context detecting the environment in which the matching is to occur, matching the detected context to a concept list appropriate to the detected context, using the concept list to transform the one or more structured descriptions into reduced structured descriptions, matching the one or more reduced structured descriptions; and providing an output representing the matching between the structured descriptions. This allows for simplification in matching process which reduces bandwidth requirements as the services requested or accessed are reduced depending on the requestors context.