We study matching in flat theories both from theoretical and practical points of view. A flat theory is defined by the axiom f(x, f(y), z) . = f(x, y, z) that indicates that nested occurrences of the function symbol f can be flattened out. From the theoretical side, we design a procedure to solve a system of flat matching equations and prove its soundness, completeness, and minimality. The mini...

In recent years, public interest in aged apartment remodeling has come to rise in Korea with the government’s strict regulation to restrict apartment reconstruction. To meet the rising demands on apartment remodeling, we attempt in this paper to develop an analytical research and schematic application of extension types for domestic apartment building stocks. Our research adopts a typological a...

Motivated by recent increases in population density and changes in urban development patterns, I give an update to Schelling’s landmark spatial segregation model. Inspired by the rapid construction of high-rise condominiums and apartments, I show a correlation between population density and racial diversity in San Diego neighborhoods. Using this as a basis, I give a modified high-density versio...

Recently two different concepts of covers of acts over monoids have been studied by a number of authors and many interesting results discovered. One of these concepts is based on coessential epimorphisms and the other is based on Enochs’ definition of a flat cover of a module over a ring. Two recent papers have suggested that in the former case, strongly flat covers are not unique. We show that...

Economic theory suggests that the use of flat-rate compensation for military recruiters is sub-optimal. We elicited the preferences of U.S. Navy recruiters for a piece-rate compensation scheme, and find many would prefer a modest decrease in fixed salary in exchange for the opportunity to receive a small monetary bonus per high-quality recruit. Under such a bonus scheme, the Navy could hire few...

This paper investigates some major changes in the wealth distribution in China using the data from two national household surveys conducted in 1995 and 2002. The surveys collected rich information on household wealth and its components, enabling a detailed analysis of changes in wealth distribution among Chinese households. Our analysis indicates that the wealth distribution in China as a whole...

This paper introduces an artificial payment card market in which we model the interactions between consumers, merchants and competing card issuers with the aim of determining the optimal pricing structure for card issuers. We allow card issuers to charge consumers and merchants with fixed fees, provide net benefits from card usage and engage in marketing activities. The demand by consumers and ...