More than half of all US import relationships begin with less than $10,000 annually. The median relationship is observed to last just one year. The incidence and duration of these relationships are consistent with a search model of international trade. The preponderance of small starting relationships reveals uncertainty present in formation of trade relationships. Initial size, reliability, an...

ecause weather and climate effects may result in spatial and temporal changes in human disease incidence, it is important to consider them when determining whether disease outbreaks are due to natural causes or to bioterrorism. Some diseases (e.g., vectorborne) respond almost directly to environmental parameters. Weather conditions also may result in increased disease incidence by stressing a p...

Schoute (1911) introduced the permutahedron on an n-element set N= { 1, . . . , n} as follows. With any permutation n of N we associate an incidence vector x(71) = (n(I), *.., n(n)) E IR”. The permutahedron is the polytope Perm(N) = conv{x(rr): rr is a permutation of N}. Independently, several authors (cf., e.g., Rado [4], Balas [l], Gaiha and Gupta [2], Young [6]) studied the permutahedron and...

The problem of characterizing the closed 2-cell E2 as an irreducible lc-connexe about a 1-sphere using unicoherence and not assuming compactness was proposed by Professor R. L. Wilder. It is found in Theorem 1 that a semi-peanian space in which all 1-spheres are contained in lc-connexes which are irreducible relative to certain unicoherence properties and satisfy a certain incidence relation an...

Incidence Calculus and Dempster-Shafer Theory of Evidence are both theories to describe agents' de­ grees of belief in propositions, thus being appropri­ ate to represent uncertainty in reasoning systems. This paper presents a straightforward equivalence proof between some special cases of these theories.