A ring satisfying x = x is necessarily commutative. We consider a variety of weaker forms of this condition and show that many but not all of them imply commutativity. We also present a variety of elementary proofs of the fact that x = x implies commutativity.

The paper investigates a concurrent computation model, chi calculus, in which communications resemble cut eliminations for classical proofs. Two bisimilarities, local bisimilarity and barbed bisimilarity, on chi processes are studied and are shown to be congruence relations. The former equivalence turns out to be strictly stronger than the latter. It is shown that chi calculus is capable of mod...

We consider the following obstacle problem for Monge-Ampere equation detDu = fχ{u>0} and discuss the regularity of the free boundary ∂{u = 0}. We prove that ∂{u = 0} is C if f is bounded away from 0 and ∞, and it is C if f ≡ 1.

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DRASTIC DEVICE SHRINKING, lower power supply levels, and increasing operating speeds significantly reduce noise margins and increase variations in process, device, and design parameters. These trends lead to lower reliability and higher design uncertainty for hardware components. With further technology scaling, high variability and low reliability are bound to become the predominant challenges...

The largest in-depth cross-cultural study of the 20th Century, directed by psychologist Charles Osgood at the University of Illinois, demonstrated that the affective meanings of concepts vary along three dimensions within all 30 cultures considered in the project, and for individuals responding in more than 21 languages. I analyze data on 17 cultures from this project in order to get some insig...

It is assumed that DNA sequences are conserved in the diverse cell types present in a multicellular organism like the human being. Thus, in order to compare the sequences in the genome of DNA from different individuals, nucleic acid is commonly isolated from a single tissue. In this regard, blood cells are widely used for this purpose because of their availability. Thus blood DNA has been used ...

We explore the effects of non-abelian dynamics of D-branes on their stability and introduce Hitchin-like modifications to previously-known stability conditions. The relation to brane-antibrane systems is used in order to rewrite the equations in terms of superconnections and arrive at deformed vortex equations.

Seeing begins in the photoreceptors, where light is absorbed and signaled to the nervous system. Throughout the animal kingdom, photoreceptors are diverse in design and purpose. Nonetheless, phototransduction-the mechanism by which absorbed photons are converted into an electrical response-is highly conserved and based almost exclusively on a single class of photoproteins, the opsins. In this R...