Deductive inference production from texts is a process considered to involve either the construction of an integrated mental model or the step-by-step coordination of propositional representations of the sentences. These alternative hypotheses were tested in 3 experiments using a set inclusion task paradigm in which participants had to recall the premises and to evaluate transitive inferences. Contrary to what is known about linear ordering relations, order of recalls and reaction times provide evidence that the encoding of set inclusion relations does not result in an integrated representation. These results suggest that the mental models theory needs to take account of the nature of the relation to be represented if it is to become a general theory of reasoning.