A Characteristic free approach for skew-gentle algebras

In this article, we write an explicit recollement for the derived category of every skew-gentle algebra. As an application, we show that gentle algebras and skew-gentle algebras share some common properties independent of the characteristic of the field. For example, all skew-gentle algebras are Gorenstein. An indecomposable skew-gentle algebra is selfinjective if and only if the set of special loops is empty and the corresponding gentle algebra is selfinjective. Finally, we show that the finitistic dimension conjecture and the Auslander-Reiten conjecture hold for all skew-gentle algebras.Comment: 20 page

Derived equivalences between matrix subrings and their applications

In this paper, we construct derived equivalences between matrix subrings. As applications, we calculate the global dimensions and the finitistic dimensions of some matrix subrings. And we show that the finitistic dimension conjecture holds for a class of Harada algebras and a class of tiled triangular algebras.Comment: 16 page

Assessing the effect of lens mass model in cosmological application with updated galaxy-scale strong gravitational lensing sample

By comparing the dynamical and lensing masses of early-type lens galaxies, one can constrain both the cosmological parameters and the density profiles of galaxies. We explore the constraining power on cosmological parameters and the effect of the lens mass model in this method with 161 galaxy-scale strong lensing systems, which is currently the largest sample with both high resolution imaging and stellar dynamical data. We assume a power-law mass model for the lenses, and consider three different parameterizations for $\gamma$ (i.e., the slope of the total mass density profile) to include the effect of the dependence of $\gamma$ on redshift and surface mass density. When treating $\delta$ (i.e., the slope of the luminosity density profile) as a universal parameter for all lens galaxies, we find the limits on the cosmological parameter $\Omega_m$ are quite weak and biased, and also heavily dependent on the lens mass model in the scenarios of parameterizing $\gamma$ with three different forms. When treating $\delta$ as an observable for each lens, the unbiased estimate of $\Omega_m$ can be obtained only in the scenario of including the dependence of $\gamma$ on both the redshift and the surface mass density, that is $\Omega_m = 0.381^{+0.185}_{-0.154}$ at 68\% confidence level in the framework of a flat $\Lambda$CDM model. We conclude that the significant dependencies of $\gamma$ on both the redshift and the surface mass density, as well as the intrinsic scatter of $\delta$ among the lenses, need to be properly taken into account in this method.Comment: Accepted for publication in MNRAS; 17 pages, 5 figures, 2 table

Revision on palaearctic species of Periclistus Förster with description of a new species and its host plant gall (Hymenoptera, Cynipidae)

Palaearctic species of Periclistus Förster has been systematically described, but a new inquiline gall-wasp, Periclistus qinghainensis sp. n., is described from China. This species was obtained from an unknown stem gall induced on Rosa sp. Diagnosis, distribution and biology of the new species are described in this paper. After examining the types of P. idoneus Belizin, 1973 and P. capillatus Belizin, 1968, it is concluded that P. idoneus belongs to genus Aulacidea, and P. capillatus is a valid species of Periclistus. A key to the Palaearctic Periclistus species is also given