Faithful ideal models for recursive polymorphic types

Ideal models are explored for a programming language with recursive polymorphic types, variants of the model studied by D. MacQueen et al. (Inf. Control, vol.71, pp.95-130, 1986). The use of suitable ideals yields a close fit between models and programming language. Two of the authors' semantics of type expressions are faithfully, in the sense that programs that behave identically in all contexts have exactly the same types.<
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