Endogenous income taxes and indeterminacy in dynamic models: When Diamond meets Ramsey again.

This paper introduces fiscal increasing returns, through endogenous labor income tax rates as in Schmitt-Grohe and Uribe (1997), into the overlapping generations model with endogenous labor, consumption in both periods of life and homothetic preferences (e.g., Lloyd-Braga, Nourry and Venditti, 2007). We show that under numerical calibrations of the parameters, local indeterminacy can occur for distortionary tax rates that are empirically plausible for the U.S. economy, provided that the elasticity of capital-labor substitution and the wage elasticity of the labor supply are large enough, and the elasticity of intertemporal substitution in consumption is slightly greater than unity. These indeterminacy conditions are similar to those obtained within infinite horizon models and from this point of view, Diamond meets Ramsey again.Indeterminacy; Endogenous labor income tax rate.

Distinct Spin Liquids and their Transitions in Spin-1/2 XXZ Kagome Antiferromagnets

By using the density matrix renormalization group, we study the spin-liquid phases of spin-$1/2$ XXZ kagome antiferromagnets. We find that the emergence of spin liquid phase does not depend on the anisotropy of the XXZ interaction. In particular, the two extreme limits---Ising (strong $S^z$ interaction) and XY (zero $S^z$ interaction)---host the same spin-liquid phases as the isotropic Heisenberg model. Both the time-reversal-invariant spin liquid and the chiral spin liquid with spontaneous time-reversal symmetry breaking are obtained. We show they evolve continuously into each other by tuning the second- and third-neighbor interactions. At last, we discuss the possible implication of our results on the nature of spin liquid in nearest neighbor XXZ kagome antiferromagnets, including the most studied nearest neighbor spin-$1/2$ kagome anti-ferromagnetic Heisenberg model

Are Progressive Income Taxes Stabilizing? : A Reply

Dromel and Pintus [Are Progressive Income Taxes Stabilizing?, Journal of Public Economic Theory 10, (2008) 329-349] have shown that labor-income tax progressivity reduces the likelihood of local indeterminacy, sunspots and cycles in a one sector monetary economy with constant returns to scale. In this note, we extend Dromel and Pintus (2008) into a two sector monetary economy with constant returns to scale studied by Bosi et al. (2007) and reassess the stabilizing effect of progressive income taxes. We show that the result in Dromel and Pintus (2008) is robust to this extension, which means that changes of the production structure won't affect the stabilizing effect of progressive income taxes, i.e., tax progressivity (regressivity) reduces (increases) the likelihood of local indeterminacy, sunspots and cycles.Tax Progressivity, local indeterminacy

Externalities, income taxes and indeterminacy in OLG models

Using an aggregate two-periods overlapping generations model with endogenous labor, consumption in both periods of life, homothetic preferences and productive external effects [Lloyd-Braga et al., 2007. Indeterminacy in dynamic models: When Diamond meets Ramsey. Journal of Economic Theory 134, 513-536], we examine the effects of alternative government financing methods on the range of values of increasing returns leading to indeterminacy. We show that under a large enough share of first period consumption over the wage income, local indeterminacy can easily occur for mild externalities if constant government expenditure is financed through either labor or capital income taxes. More precisely, we show that, with labor income taxes and mild externalities, small government expenditures are helpful to local indeterminacy, while large government expenditures are useful to stabilize the economy. With capital income taxes and mild externalities, local indeterminacy always exists. Moreover, we explore how our previous results are changed once government expenditure is endogenously determined for fixed rates on labor and capital income under the balanced-budget rule.Indeterminacy; Endogenous income tax rates; Externalities.

Complexity Analysis of Reed-Solomon Decoding over GF(2^m) Without Using Syndromes

For the majority of the applications of Reed-Solomon (RS) codes, hard decision decoding is based on syndromes. Recently, there has been renewed interest in decoding RS codes without using syndromes. In this paper, we investigate the complexity of syndromeless decoding for RS codes, and compare it to that of syndrome-based decoding. Aiming to provide guidelines to practical applications, our complexity analysis differs in several aspects from existing asymptotic complexity analysis, which is typically based on multiplicative fast Fourier transform (FFT) techniques and is usually in big O notation. First, we focus on RS codes over characteristic-2 fields, over which some multiplicative FFT techniques are not applicable. Secondly, due to moderate block lengths of RS codes in practice, our analysis is complete since all terms in the complexities are accounted for. Finally, in addition to fast implementation using additive FFT techniques, we also consider direct implementation, which is still relevant for RS codes with moderate lengths. Comparing the complexities of both syndromeless and syndrome-based decoding algorithms based on direct and fast implementations, we show that syndromeless decoding algorithms have higher complexities than syndrome-based ones for high rate RS codes regardless of the implementation. Both errors-only and errors-and-erasures decoding are considered in this paper. We also derive tighter bounds on the complexities of fast polynomial multiplications based on Cantor's approach and the fast extended Euclidean algorithm.Comment: 11 pages, submitted to EURASIP Journal on Wireless Communications and Networkin