I am a graduate student working in the area of categorical models of process behavior. One of the models I am looking at is the topos of labeled trees (cf. Enriched Categorical Semantics for Distributed Calculi, S.Kasangian and A.Labella, to appear in Jn. of Pure and Algebra). In this paper and elsewhere there are references to unpublished manuscripts of Benabou, which are difficult to get hold of. My question is regarding the subobject classifier in this topos of labeled trees : What does it look like, for a given set of labels A? Also, are there any published works on the topos of labeled trees where its properties are spelled out in detail? Any help will be greatly appreciated. Sincerely, Purandar Bhaduri. ===================================