A global action is the algebraic analogue of a topological manifold. This construction was introduced in first place by A. Bak as a combinatorial approach to K-Theory and the concept was later generalized by Bak, Brown, Minian and Porter to the notion of groupoid atlas. In this paper we define and investigate homotopy invariants of global actions and groupoid atlases, such as the strong fundame...

The groupoid interpretation of Martin-Löf type theory not only shows the independence of uniqueness of identity proofs from the axioms of intensional type theory but is also constructive and validates the computation rules as definitional equalities. The groupoid semantics are very clear when interpreting dependent types and in particular the identity types but less so when defining equality pr...

In this work we prove that the set of congruences on an nd-groupoid under suitable conditions is a complete lattice which is a sublattice of the lattice of equivalence relations on the nd-groupoid. The study of these conditions allowed to construct a counterexample to the statement that the set of (fuzzy) congruences on a hypergroupoid is a complete lattice.

Orbifold groupoids have been recently widely used to represent both effective and ineffective orbifolds. We show that every orbifold group-oid can be faithfully represented on a continuous family of finite dimensional Hilbert spaces. As a consequence we obtain the result that every orbifold groupoid is Morita equivalent to the translation groupoid of an action of a bundle of compact topological...

In this paper, we apply the theory of inverse semigroups to the C∗-algebra U [Z] considered in [Cun08]. We show that the C∗-algebra U [Z] is generated by an inverse semigroup of partial isometries. We explicity identify the groupoid Gtight associated to the inverse semigroup and show that Gtight is exactly the same groupoid obtained in [CL10].

Opposite the title page of J. W. Ocker’s Poe-Land: The Hallowed Haunts Edgar Allan Poe, readers will find a photograph snowman made up like harbinger what is to follow in this modern-day travel book that entertainingly describes places associated with life and works Poe. It by fan Poe for fans written decidedly engaging style. “I Poe,” says Ocker his introduction. “So there’ll be lot hagi ograp...

The effects of four nonionic and two anionic surfactants on cucumber protoplasts were examined by light and electron microscopy. Two nonionic surfactants, polyoxyethylene (POE) (n=10) nonylphenylether and POE (n=5) laurylether, caused swelling of protoplasts, followed by their bursting. The bursting gave more destructive effects preferentially on lamellar structures of chloroplasts than the swe...

This exploratory study aimed to develop and test a quick, easily administered instrument, the Index of Problematic Online Experiences (I-POE). The goal of the I-POE extends beyond assessing for Internet overuse to broadly assess problematic Internet use across several domains and activities. Data was collected from 563 college students from a Northern New England university using an online surv...

We have developed the Rabbit Corneal Epithelial (RCE) Model to evaluate the in vitro eye irritation potential of chemicals including pharmaceuticals, cosmetics and their raw ingredients. In the model, a stratified culture of rabbit corneal epithelial cells is grown at the air-liquid interface on an amnion acting as a parabasal membrane. The alkaline exposure was restored each day in the presenc...

This is a sequel to the paper [6] ‘Homology of types in model theory I: Basic concepts and connections with type amalgamation’. We compute the group H2 for strong types in stable theories and show that any profinite abelian group can occur as the group H2 in the model-theoretic context. The work described in this paper was originally inspired by Hrushovski’s discovery [8] of striking connection...