Let I be a small indexing category, G : I → Cat be a functor and BG ∈ Cat denote the Grothendieck construction on G. We define and study Quillen pairs between the category of diagrams of simplicial sets (resp. categories) indexed on BG and the category of I-diagrams over N(G) (resp. G). As an application we obtain a Quillen equivalence between the categories of presheaves of simplicial sets (re...

We relate three different, but equivalent, ways to characterise behavioural equivalence for set coalgebras. These are: using final coalgebras, using coalgebraic languages that have the HennessyMilner property and using coalgebraic languages that have “logical congruences”. On the technical side the main result of our paper is a straightforward construction of the final T -coalgebra of a set fun...

Gabbay and Pitts proved that lambda-terms up to alphaequivalence constitute an initial algebra for a certain endofunctor on the category of nominal sets. We show that the terms of the infinitary lambda-calculus form the final coalgebra for the same functor. This allows us to give a corecursion principle for alpha-equivalence classes of finite and infinite terms. As an application, we give corec...

We clarify in which precise sense the theory of principal bundles and the theory of groupoids are equivalent; and how this equivalence of theories, in the differentiable case, reflects itself in the theory of connections. The method used is that of synthetic differential geometry. Introduction. In this note, we make explicit a sense in which the theory of principal fibre bundles is equivalent t...

This paper gives a uniform-theoretic refinement of classical homotopy theory. Both cubical sets (with connections) and uniform spaces admit classes weak equivalences, special cases appropriate for the respective Lipschitz settings. Cubical additional compatible structures categories (co)fibrant objects. A categorical equivalence between lifts to full faithful embedding from an associated catego...

There are several ways to construct omega-categories from combinatorial objects such as pasting schemes or parity complexes. We make these constructions into a functor on a category of chain complexes with additional structure, which we call augmented directed complexes. This functor from augmented directed complexes to omega-categories has a left adjoint, and the adjunction restricts to an equ...

Transactional graph transformation systems (t-gtss) have been recently proposed as a mild extension of the standard dpo approach to graph transformation, equipping it with a suitable notion of atomic execution for computations. A typing mechanism induces a distinction between stable and unstable items, and a transaction is defined as a shift-equivalence class of computations such that the start...

Modal logic has a good claim to being the logic of choice for describing the reactive behaviour of systems modeled as coalgebras. Logics with modal operators obtained from so-called predicate liftings have been shown to be invariant under behavioral equivalence. Expressivity results stating that, conversely, logically indistinguishable states are behaviorally equivalent depend on the existence ...

We introduce the generalized Serre functor S on a skeletally-small Hom-finite Krull-Schmidt triangulated category C. We prove that its domain Cr and range Cl are thick triangulated subcategories. Moreover, the subcategory Cr (resp. Cl) is the smallest additive subcategory containing all the objects in C which appears as the third term (resp. the first term) of some Aulsander-Reiten triangle in ...

We de ne a localization L of a category E to be quintessential if the left adjoint to the inclusion functor is also right adjoint to it and persistent if L is closed under subobjects in E We show that quintessential localizations of an arbitrary Cauchy complete category correspond to idempotent natural endomorphisms of its i dentity functor and that they are necessarily persistent Our investiga...