The first and third authors and others [2,8,9,10,11,12] have studied sets of “tiles” (a generalization of pixels or voxels) in two and three dimensions that have a property called strong normality (SN): For any tile P , only finitely many tiles intersect P , and any nonempty intersection of these tiles must also intersect P . This paper presents extensions of the basic results about SN sets of ...

The CXC chemokine receptor 3 (CXCR3) has been linked to autoimmune and inflammatory disease, allograft rejection, and ischemic nephropathy. CXCR3 is expressed on endothelial and smooth muscle cells. Although a recent study posited that antagonizing of CXCR3 function may reduce atherosclerosis, the role of CXCR3 in controlling physiological vascular functions remains unclear. This study demonstr...

We base a contracting theory for a start-up firm on an agency model with observable but nonverifiable effort, and renegotiable contracts. Two essential restrictions on simple contracts are imposed: the entrepreneur must be given limited liability, and the investor’s earnings must not decrease in the realized profit of the firm. All message game contracts with pure strategy equilibria (and no th...

We base a contracting theory for a start-up firm on an agency model with observable but nonverifiable effort, and renegotiable contracts. Two essential restrictions on simple contracts are imposed: the entrepreneur must be given limited liability, and the investor’s earnings must not decrease in the realized profit of the firm. All message game contracts with pure strategy equilibria (and no th...

A graph containment problem is that of deciding whether one graph called the host graph can be modified into some other graph called the target graph by using a number of specified graph operations. We consider edge deletions, edge contractions, vertex deletions and vertex dissolutions as possible graph operations permitted. By allowing any combination of these four operations we capture the fo...

In this paper, we study the contracting issues in an outsourcing supply chain consisting of a user company and a call center that does outsourcing work for the user company. We model the call center as a G/G/s queue with customer abandonment. Each call has a revenue potential, and we model the call center’s service quality by the percentage of calls resolved (revenue realized). The call center ...

Delegation versus Authority by Daniel Krähmer The paper studies the role of delegation and authority within a principal-agent relation in which a non-contractible action has to be taken. The agent has private information relevant for the principal, but has policy preferences different from the principal. Consequently, an information revelation problem arises. We contribute to the literature by ...

We present an algorithm for the following problem. Given a triangulated 3-manifold M and a (possibly non-simple) closed curve on the boundary of M , decide whether this curve is contractible in M . Our algorithm is combinatorial and runs in exponential time. This is the first algorithm that is specifically designed for this problem; its running time considerably improves upon the existing bound...

The Induced Minor problem is that of testing whether a graph G can be modified into a graph H by a sequence of vertex deletions and edge contractions. If only edge contractions are permitted, we obtain the Contractibility problem. We prove that Induced Minor is polynomial-time solvable when G is AT-free and H is fixed, i.e., not part of the input. In addition, we show that Contractiblity is pol...