Logic has proved essential for formally modeling software based systems. Such formal descriptions, frequently called specifications, have served not only as requirements documentation and formalisation, but also for providing the mathematical foundations for their analysis and the development of automated reasoning tools. Logic is usually studied in terms of its two inherent aspects: syntax and semantics. The relevance of the latter resides in the fact that producing logical descriptions of real-world phenomena, requires people to agree on how such descriptions are to be interpreted and understood by human beings, so that systems can be built with confidence in accordance with their specification. On the more practical side, the metalogical relation between syntax and semantics, determines important aspects of the conclusions one can draw from the application of certain analysis techniques, like model checking. Abstract model theory (i.e., the mathematical perspective on semantics of logical languages) is of little practical value to software engineering endeavours. From our point of view, values (those that can be assigned to constants and variables) should not be just points in a platonic domain of interpretation, but elements that can be named by means of terms over the signature of the specification. In a nutshell, we are not interested in properties that require any semantic information not representable using the available syntax. In this paper we present a framework supporting the proof theoretical formalisation of classes of relational models for behavioural logical languages, whose domains of discourse are guaranteed to be formed exclusively by nameable values.