Spectra and symmetric spectra in general model categories

(This is an updated version; following an idea of Voevodsky, we have strengthened our results so all of them apply to one form of motivic homotopy theory). We give two general constructions for the passage from unstable to stable homotopy that apply to the known example of topological spaces, but also to new situations, such as motivic homotopy theory of schemes. One is based on the standard notion of spectra originated by Boardman. Its input is a well-behaved model category C and an endofunctor G, generalizing the suspension. Its output is a model category on which G is a Quillen equivalence. Under strong hypotheses the weak equivalences in this model structure are the appropriate analogue of stable homotopy isomorphisms. The second construction is based on symmetric spectra, and is of value only when C has some monoidal structure that G preserves. In this case, ordinary spectra generally will not have monoidal structure, but symmetric spectra will. Our abstract approach makes constructing the stable model category of symmetric spectra straightforward. We study properties of these stabilizations; most importantly, we show that the two different stabilizations are Quillen equivalent under some hypotheses (that also hold in the motivic example).Comment: 45 page

Ownership structures and the leverage of listed firms in China

In this paper the relationship between leverage, performance and a firm’s ownership structure is investigated. It is an exploratory study based on listed firms in China, that is all firms listed on the Shanghai and Shenzhen stock exchanges from 1999 to 2005. The results of an empirical analysis of ownership structures and the leverage are reported in this paper. The most significant result is that foreign holdings are found to have a significant relationship with the leverage of listed firms in China. Whereas, somewhat unexpectedly, institutional ownership, through Legal Person holding companies, state ownership and private holdings are not found to have a significant relationship with the capital structure choices of firms in China. The results also suggest that some firm-specific factors that are relevant for explaining firm leverage generally referred to in studies in developed economies, such as profitability, growth opportunities, size and tax shields, are also relevant in China. The age of the firms and the industry to which they principally belong also has significant bearing. Yet direct government grants and the use of an internationally renowned auditing firm do not show a significant relationship