Proof theory and category theory were first drawn together by Lambek some 30 years ago
but, until now, the most fundamental notions of category theory (as opposed to their …

We give a category-theoretic formulation of Engeler-style models for the untyped λ-calculus.
In order to do so, we exhibit an equivalence between distributive laws and extensions of one …

A remark on the theory of semi-functors Page 1 Math. Struct, in Comp. Science (1995), vol. 5,
pp. 1-8 Copyright © Cambridge University Press A remark on the theory of semi-functors R …

In a previous paper we introduced the concept of semiseparable functor. Here we continue
our study of these functors in connection with idempotent (Cauchy) completion. To this aim …

Fusion laws permit to eliminate various of the intermediate data structures that are created in
function compositions. The fusion laws associated with the traditional recursive operators on …

We generalize the classic Vietoris endofunctor to the category of compact Hausdorff spaces
and closed relations. The lift of a closed relation is done by generalizing the construction of …

The notion of semifunctor between categories, due to S. Hayashi (1985), is defined as a
functor that does not necessarily preserve identities. In this paper we study how several …

Refinement types are subsets of ordinary types, which are intended to be specifications of
programs. Ordinary types correspond to constructive propositions by Curry-Howard …

Example higher-order programs are presented in the style of Hoare logic and refinement
calculus, as motivation for a study of weak (lax) coexponents in categories of predicate …

We look at homotopy-coherent diagrams of spaces (after Segal, Leitch, Vogt, Mather,
Cordier) over a Grothendieck site; we call these``flexible presheaves''. After some …