Standard approaches to measuring the welfare gains from variety take variety as exogenous to consumers. Empirically we observe an Engel curve for variety, with richer consumers purchasing a larger set of varieties than poor ones. I present a tractable model for analyzing the welfare gains from variety in the presence of this non-homotheticity. The model generates variety Engel curves through di...

Task variety is a familiar concept in organization theory and in job analysis. Standardized scales to measure task variety have been developed and shown to be reliable, but results reported here suggest that while these scales may measure the number of different tasks performed, they do not measure variety in work process. Comparing results from the standard, survey-based measures and detailed,...

Retailers need to decide on the content and structure of their product assortments, and thereby on the degree of variety that they offer to their customers. This paper compares measures of assortment variety and relates them to underlying variety components. We conceptualize assortment variety from a product and an attribute perspective, compare extant measures of assortment variety, and examin...

The notion of partial plans has existed ever since the early days of planning research. However, plans can be partial in many different ways, and for many different reasons. This paper presents a characterization of partial plans and discusses the use of partial plans in incremental planning under computational and informational constraints. A heuristic for guiding the generation of plausible p...

The diversity of immunoglobulin (Ig) functions may be explained by the peculiar structure of these flexible molecules. Heavy and light Ig chains are composed from compact stable immunoglobulin folds (IgF), or domains belonging to a large protein super family. Proteins composed from IgF have been found in various representatives of animal kingdom even those appeared during the very early stages ...

In this note we settle a question posed by Hobby and McKenzie in [2] on the nature of locally finite equational classes which satisfy some nontrivial congruence identity. We settle problem #14 from [2] by exhibiting a locally finite equational class V which omits types 1 and 5 and which satisfies some non-trivial congruence identity, but which contains a finite algebra having a type 4 minimal s...

We determine normal forms and ranks of tensors of border rank at most three. We present a differential-geometric analysis of limits of secant planes in a more general context. In particular there are at most four types of points on limiting trisecant planes for cominuscule varieties such as Grassmannians. We also show that the singular locus of the secant varieties σr(Seg(P × P × P)) has codime...

Dematerialization, represented by declining consumption per GDP of energy or of goods, offers some hope for rising environmental quality with development. The declining proportion of income spent on staples as affluence grows, which income elasticity <1.0 measures, makes dematerialization widespread. Further, as learning improves efficiency of resource use, the intensity of environmental impact...