Equative
The term equative (or equational) is used in linguistics to refer to constructions where two entities are equated with each other. For example, the sentence Susan is our president, equates two entities "Susan" and "our president". In English, equatives are typically expressed using a copular verb such as "be", although this is not the only use of this verb. Equatives can be contrasted with predicative constructions where one entity is identified as a member of a set, such as Susan is a president. This view has been contrasted by Otto Jespersen in the first part of the XX century and by Giuseppe Longobardi and Andrea Moro in the second. In particular, Andrea Moro in 1988 proved that either (DP) must be non referential in the sense of Geach (1962) by exploiting arguments based on binding theory. The idea is that when a DP plays the role of predicate it enlarges its binding domain: for example, in John met his cook the pronoun can refer to the subject John but in John is his cook it cannot. The key-step was to admit that the DP following the copula can be referential whereas the one preceding must not, in other words the key-step was to admit that there can be inverse copular sentences, namely those where the subject, which is referential, follows the predicate. For a discussion starting from Moro's data see Heycock (2012). For a historical view of the development of the analysis of the copula see Moro Different world languages approach equatives in different ways. The major difference between languages is whether or not they use a copular verb or a non-verbal element (e.g. demonstrative pronoun) to equate the two expressions. The term equative is also sometimes applied to comparative-like constructions in which the degrees compared are identical rather than distinct: e.g., John is as stupid as he is blonde; some languages have a separate equative case. (Wikipedia).
