Relative Orbifold Donaldson-Thomas Theory and the Degeneration Formula

We generalize the notion of expanded degenerations and pairs for a simple degeneration or smooth pair to the case of smooth Deligne-Mumford stacks. We then define stable quotients on the classifying stacks of expanded degenerations and pairs and prove the properness of their moduli's. On 3-dimensional smooth projective DM stacks this leads to a definition of relative Donaldson-Thomas invariants and the associated degeneration formula.Comment: 59 pages. Final versio

International transmission of inflation among G-7 countries: a data-determined VAR analysis

We investigate the international transmission of inflation among G-7 countries using a data-determined vector autoregression analysis, as advocated by Swanson and Granger (1997). Over the period 1973 to 2003, we find that U.S. innovations have a large effect on inflation in the other countries, although they are not always the dominant international factor. Similarly, shocks to some other countries also have a statistically and economically significant influence on U.S. inflation. Moreover, our evidence indicates that U.S. inflation has become less vulnerable to foreign shocks since the early 1990s, mainly because of the diminished influence from Germany and FranceInternational finance ; Time-series analysis

Does aggregate relative risk aversion change countercyclically over time? evidence from the stock market

Using a semiparametric estimation technique, we show that the risk-return tradeoff and the Sharpe ratio of the stock market increases monotonically with the consumption wealth ratio (CAY) across time. While early studies have commonly interpreted such a finding as evidence of the countercyclical variation in aggregate relative risk aversion (RRA), we argue that it mainly reflects changes in investment opportunities for two reasons. First, we fail to reject the null hypothesis of constant RRA after controlling for CAY as a proxy for the hedge against changes in the investment opportunity set. Second, by contrast with habit formation models but consistent with ICAPM, we find that loadings on the conditional stock market variance scaled by CAY are negatively priced in the cross-sectional regressions. For illustration, we replicate the countercyclical stock market risk-return tradeoff using simulated data from Guo's (2004) limited stock market participation model, in which RRA is constant and CAY is a proxy for shareholders' liquidity conditions.Capital assets pricing model ; Stock market