A critical view of the alleged significance of Belnap four-valued logic for reasoning under inconsistent and incomplete information is provided. The difficulty lies in the confusion between truth-values and information states, when reasoning about Boolean propositions. So our critique is along the lines of previous debates on the relevance of many-valued logics and especially of the extension o...

Erdős, Purdy, and Straus conjectured that the number of distinct (nonzero) areas of the triangles determined by n noncollinear points in the plane is at least b 2 c, which is attained for dn/2e and respectively bn/2c equally spaced points lying on two parallel lines. We show that this number is at least 17 38 n − O(1) ≈ 0.4473n. The best previous bound, ( √ 2 − 1)n − O(1) ≈ 0.4142n, which dates...

A projective bundle in PG(2, q) is a collection of q + q + 1 conics that mutually intersect in a single point and hence form another projective plane of order q. The purpose of this paper is to investigate the possibility of partitioning the q5 − q2 conics of PG(2, q) into q2(q − 1) disjoint projective bundles. As a by-product we obtain a multiplier theorem for perfect difference sets that gene...

Theory is critical to science. Group Support Systems (GSS), as a field of scientific inquiry is no exception. The important issue about theory in GSS is then not why theory, but where should theory come from (or how should theory be developed) and how to assess it (or evaluate its usefulness). This paper expounds on these issues by considering various approaches to theorizing about GSS, and del...

Workers' compensation insurance provides cash benefits and health care for workers who are injured on the job. This DataWatch considers the costs and benefits of combining the health insurance component of workers' compensation with universal health insurance, creating a twenty-four-hour coverage plan. The paper documents a large potential savings from twenty-four-hour coverage: Workers' compen...

Grounded in the 2x2 achievement goal framework (Elliot & McGregor, 2001), a model was tested examining the hypothesized relationships between approach and avoidance (mastery and performance) goals, challenge and threat appraisals of sport competition, and positive and negative indices of well-being (i.e., self-esteem, positive, and negative affect). A further aim was to determine the degree to ...

A few years ago, Tzeng settled a remarkable conjecture of Goettsche on counting nodal curves on smooth surfaces, proving that the formulas are given by certain universal polynomials. At the same time, Ardila and Block used the tropical approach of Brugalle, Mihalkin and Fomin to count nodal curves on a certain class of (not necessarily smooth) toric surfaces, and obtained similar polynomiality ...

The aim of this study was to assess the relationship between blood pressure measured conventionally ('conventional' pressure) and 24 h ambulatory blood pressure measured with the SpaceLabs 90202 recorder, in a control population with normal blood pressure, and in patients with hypertension. Reference values for 24 h ambulatory blood pressure had been determined previously in a control populatio...

The no-zero-divisor division algebra of highest possible dimension over the reals is taken as a model for various physical and mathematical phenomena mostly related to the Four Color Conjecture. A geometric form of associativity is the common thread.