The E6E_6 state sum invariant of lens spaces

In this paper, we calculate the values of the $E_6$ state sum invariants for the lens spaces $L(p,q)$. In particular, we show that the values of the invariants are determined by $p \mod 12$ and $q \mod (p,12)$. As a corollary, we show that the $E_6$ state sum is a homotopy invariant for the oriented lens spaces.Comment: 6 pages, 0 figure

Membrane Quantum Mechanics

We consider the multiple M2-branes wrapped on a compact Riemann surface and study the arising quantum mechanics by taking the limit where the size of the Riemann surface goes to zero. The IR quantum mechanical models resulting from the BLG-model and the ABJM-model compactified on a torus are N = 16 and N = 12 superconformal gauged quantum mechanics. After integrating out the auxiliary gauge fields we find OSp(16|2) and SU(1,1|6) quantum mechanics from the reduced systems. The curved Riemann surface is taken as a holomorphic curve in a Calabi-Yau space to preserve supersymmetry and we present a prescription of the topological twisting. We find the N = 8 superconformal gauged quantum mechanics that may describe the motion of two wrapped M2-branes in a K3 surface.Comment: 54 pages, v2: errors corrected and notations improve

Holding Company and Bank: An Historical Comparative Perspective on Corporate Governance in Japan, subsequently published in "Seoul Journal of Economics", 2004, vol.17-3. )

In this paper I describe the outline of the historical evolution of corporate governance in Japan, and intend to derive some insights on its future. While two alternative systems, the holding company-based system and the bank-based system were available in the 1920s, the former started to proliferate. However, the experiences during the Second World War made the corporate system choose the other fork in the road, the bank-based system. The changes in employment system and production management were complementary with the changes in corporate governance and finance. The Japanese corporate system, which was faced with a bifurcation in the 1920s and the 1930s, is now facing another bifurcation.

"Ownership Changes and Economic Efficiency: Plant-Level Evidence from the Japanese Cotton Spinning Industry, 1900-1911"

This paper investigates how ownership changes affect the plant performance, focusing on the cotton spinning industry in early twentieth century Japan, where many plants experienced ownership changes. Through analyses of detailed plant-level data, it is revealed that, after ownership changes, plants tended to focus on low grade and low price products and, at the same time, total factor productivity, machine productivity and profitability of the plants significantly increased. These results indicate that the plants were managed and utilized more efficiently under the new ownership.

"The Role of the Merchant Coalition in Premodern Japanese Economic Development: An Historical Institutional Analysis"

This paper analyzes the role of the merchant coalition (kabu nakama) in Japan in the eighteenth and the first half of the nineteenth century, from the standpoint of Historical Institutional Analysis (Greif[1997]). The quantitative economic history literature has made clear that sustainable economic growth based on a market economy started in Japan at the end of the eighteenth century. On the other hand, from time to time the central government (Bakufu) legislated ordinances prescribing that suits on pecuniary matters would not be accepted (Aitai Sumeshi Rei). The implication is that the public system for third-party contract enforcement was not working well. The activities of merchant coalitions substituted for public third-party enforcement in premodern Japan. Many of the merchant coalitions' codes prescribed that all of each coalition's members should suspend transaction with those who cheated any one of the members of the coalition. This was the multiple punishment strategy (MPS), as formulated by Greif[1993]. The MPS of the merchant coalition reduced incentives for the players in the market to cheat, which in turn promoted development of a market economy. It is remarkable that the Japanese merchant coalition applied the MPS not only to ordinary commodity trade, but also to the putting-out system and employment. We empirically tested the above hypothesis about the function of the coalition. In 1841, the Bakufu prohibited the coalition, intending to eliminate any monopoly. This event can be regarded as a natural experiment, suitable for an investigation into the role of the coalition. The above hypothesis implies that prohibition of the coalition lowered the performance of the market economy. This implication was examined using data on the money supply and commodity prices. As predicted by the hypothesis, we found that the growth rate of the real money supply contracted and that the efficiency of price arbitrage declined.

""Voice" and "Exit" in Japanese Firms during the Second World War: Sanpo Revisited"

During the Second World War, the Japanese government and private sector searched for and implemented new mechanisms for coordination and motivation. One of these was sangyo hokokukai (sanpo). Sanpo unit was basically an organization of the employer and employees of each firm, which held meetings to moderate labor relations. Due to the government policy to promote sanpo units, around 70% of the total workers in Japan were organized into sanpo units in the early 1940s. As the members of labor unions and the workers of the companies which had factory committees, were only 7 % and 5% of the total workers in 1936 respectively, sanpo was the first large scale mechanism for Japanese employees to voice. In this paper, I examined the role of sanpo, using prefecture level data and firm level data, based on a framework integrating the "voice view" of unionism and the transaction cost economics. It was found that sanpo reduced the participation rate in labor disputes, and enhanced labor productivity at least in some period.