Inspired by decomposition problems in rule-based formalisms in Computational Systems Biology and recent work on compositionality in graph transformation, this paper proposes to use arbitrary colimits to “deconstruct” models of reactions in which states are represented as objects of adhesive categories. The fundamental problem is the decomposition of complex reactions of large states into simple...

This paper studies fundamental connections between profunctors (i.e., distributors, or bimodules), open maps and bisimulation. In particular, it proves that a colimit preserving functor between presheaf categories (corresponding to a profunctor) preserves open maps and open map bisimulation. Consequently, the composition of profunctors preserves open maps as 2-cells. A guiding idea is the view ...

These notes were written to accompany two talks given in the Algebraic Topology and Category Theory Proseminar at the University of Chicago in Winter 2009. When a category has some notion of limits and colimits associated to it, its ordinary limits and colimits are not necessarily homotopically meaningful. We describe a notion of a “homotopy colimit” for two sorts of categories with a homotopy ...

We present a general approach for representing, composing, and computing alignments, based on the category theoretic notions of diagram, pushout, and colimit. This generalises the possible ‘shapes’ of alignments that have been introduced previously in similar approaches. We use the theory of institutions to represent heterogeneous ontologies, and show how the tool Hets can be employed to comput...

let $s$ be a monoid. in this paper, we prove every class of $s$-acts having a flatness property is closed underdirected colimits, it extends some known results. furthermore thisresult implies that every $s$-act has a flatness cover if and only if it has a flatness precover.

We recall a group-theoretic description of the first non-vanishing homotopy group of a certain (n+1)-ad of spaces and show how it yields several formulae for homotopy and homology groups of specific spaces. In particular we obtain an alternative proof of J. Wu’s group-theoretic description of the homotopy groups of a 2-sphere.

In 1973 William Lawvere published a paper (reprinted as (Lawvere 2002)) where he explained that partial orders and metric spaces are examples of categories enriched in a closed category. Indeed, preorders are categories enriched over the two-element Boolean algebra 2, while (generalized) metric spaces are categories enriched over ([0,∞],+). Lawvere’s idea has been extremely influential in the f...

Finitary sketches, i.e., sketches with nite-limit and nite-colimit specii-cations, are proved to be as strong as geometric sketches, i.e., sketches with nite-limit and arbitrary colimit speciications. Categories sketchable by such sketches are fully characterized in the innnitary rst-order logic: they are axiomatizable by-coherent theories, i.e., basic theories using nite conjunctions, countabl...