Inflation and Unemployment in Competitive Search Equilibrium

Using a monetary search model, Rocheteau, Rupert and Wright (2007) show that the relationship between inflation and unemployment can be positive or negative depending on the primitives of the model. The key features are indivisible labor, nonseparable preferences and bargaining. Their results are derived only for a special case of the bargaining solution, take-it-or-leave-it offer by buyers. Instead of bargaining, this paper considers competitive search (price posting with directed search). I show that the results in Rocheteau, Rupert and Wright (2007) can be generalized in an environment where both buyers and sellers have nonseparable preferences. In addition, the relationship between inflation and unemployment is robust to allowing free entry by sellers, which cannot be studied in Rocheteau, Rupert and Wright (2007).Inflation: costs and benefits

Money and Costly Credit

I study an economy in which money and credit coexist as means of payment and the settlement of credit requires money. The model extends recent developments in microfounded monetary theory to address the choice of payment methods and the effects of inflation. Whether a buyer uses money or credit depends on the fixed cost of credit and the inflation rate. In particular, inflation not only makes money less valuable, but also makes credit more expensive because of delayed settlement. Based on quantitative analysis, the model suggests that the relationship between inflation and credit exhibits an inverse U-shape which is broadly consistent with anecdotal evidence. Compared to an economy without credit, allowing credit as a means of payment has three implications: [1] it lowers money demand at low to moderate inflation rates; [2] it improves society’s welfare when the inflation rate exceeds a specific threshold; and [3] it can raise the welfare cost of inflation for some reasonable values of the credit cost parameter.Credit and credit aggregates; Inflation: costs and benefits

A Study of Active Galactic Nuclei in Low Surface Brightness Galaxies with Sloan Digital Sky Survey Spectroscopy

Active galactic nuclei (AGN) in low surface brightness galaxies (LSBGs) have received little attention in previous studies. In this paper, we present detailed spectral analysis of 194 LSBGs from the Impey et al. (1996) APM LSBG sample which have been observed spectroscopically by the Sloan Digital Sky Survey Data Release 5 (SDSS DR5). Our elaborate spectral analysis enables us to carry out, for the first time, reliable spectral classification of nuclear activities in LSBGs based on the standard emission line diagnostic diagrams in a rigorous way. Star-forming galaxies are common, as found in about 52% LSBGs. We find, contrary to some of the previous claims, that the fraction of galaxies containing an AGN is significantly lower than that found in nearby normal galaxies of high surface brightness. This is qualitatively in line with the finding of Impey et al. (2001). This result holds true even within each morphological type from Sa to Sc. LSBGs having larger central stellar velocity dispersions, or larger physical sizes, tend to have a higher chance to harbor an AGN. For three AGNs with broad emission lines, the black hole masses estimated from the emission lines are broadly consistent with the well known M-$\sigma_\ast$ relation established for normal galaxies and AGNs.Comment: 5 tables and 14 figure

Riemann-Liouville Fractional Cosine Functions

In this paper, a new notion, named Riemann-Liouville fractional cosine function is presented. It is proved that a Riemann-Liouville $\alpha$-order fractional cosine function is equivalent to Riemann-Liouville $\alpha$-order fractional resolvents introduced in [Z.D. Mei, J.G. Peng, Y. Zhang, Math. Nachr. 288, No. 7, 784-797 (2015)]