Editorial v. 14, n. 3

$n$-cocoherent rings‎, ‎$n$-cosemihereditary rings and $n$-V-rings

 Let $R$ be a ring‎, ‎and let $n‎, ‎d$ be non-negative integers‎. ‎A right $R$-module $M$ is called $(n‎, ‎d)$-projective if $Ext^{d+1}_R(M‎, ‎A)=0$ for every $n$-copresented right $R$-module $A$‎. ‎$R$ is called right $n$-cocoherent if every $n$-copresented right $R$-module is $(n+1)$-coprese-nted‎, ‎it is called a right co-$(n,d)$-ring if every right $R$-module is $(n‎, ‎d)$-projective‎. ‎$R$...

v 3 9 N ov 1 99 3 CTP # 2243

The quantization of a massless conformally coupled scalar field on the 2+1 dimensional Anti de Sitter black hole background is presented. The Green’s function is calculated, using the fact that the black hole is Anti de Sitter space with points identified, and taking into account the fact that the black hole spacetime is not globally hyperbolic. It is shown that the Green’s function calculated ...

Editorial note Volume 6 Issue 3

ar X iv : 0 90 6 . 42 14 v 1 [ he p - ex ] 2 3 Ju n 20 09

The cross sections for the reactions ee → φη, φη, ρη, ρη have been measured using a data sample of 516 fb collected with the Belle detector at the KEKB asymmetric-energy ee collider. The corresponding values of the cross sections are: 1.4± 0.4± 0.1 fb (φη), 5.3± 1.1± 0.4 fb (φη), 3.1± 0.5± 0.1 fb (ρη) and 3.3± 0.6± 0.2 fb (ρη). The energy dependence of the cross sections is presented using Bell...

02 14 2 v 3 1 4 Ju n 20 01 Field theory models for variable cosmological constant

Anthropic solutions to the cosmological constant problem require seemingly unnatural scalar field potentials with a very small slope or domain walls (branes) with a very small coupling to a four-form field. Here we introduce a class of models in which the smallness of the corresponding parameters can be attributed to a spontaneously broken discrete symmetry. We also demonstrate the equivalence ...