Is a monotone union of contractible open sets contractible?

A Stably Contractible C*-algebra Which Is Not Contractible

We exhibit a separable commutative C*-algebra A such that A⊗K is homotopy equivalent to zero, without Mn(A) being so for any n ≥ 1.

Open Contractible Global Constraints

Open forms of global constraints allow the addition of new variables to an argument during the execution of a constraint program. Such forms are needed for difficult constraint programming problems where problem construction and problem solving are interleaved. However, in general, filtering that is sound for a global constraint can be unsound when the constraint is open. This paper provides a ...

Cartesian Products of Contractible Open Manifolds

Denable and Contractible Contracts

This paper analyzes Bayesian normal form games in which players write contracts that condition their actions on the contracts of other players. These contracts are required to be representable in a formal language. This is accomplished by constructing contracts which are de…nable functions of the Godel code of every other player’s contract. We provide a complete characterization of the set of a...

Contractible Exact Squares

Exact squares in Cat are not necessarily absolute (i.e. preserved by any 2-functor Cat→ Cat), or even preserved by any 2-functor given by exponentiation (−)I : Cat → Cat: if a square is preserved by exponentiation it will be called a contractible exact square. We will characterize diagrammatically these contractible squares, and among them the contractible categories, and the so called fibering...