Editorial, v. 13, n. esp. 3, dez. (2018)

$n$-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. ‎$R$...

arXiv : hep - ph / 0005327 v 3 13 Jun 2000 1

We are answering the question why 4-dimensional space has the metric 1+ 3 by making a general argument from a certain type of equations of motion linear in momentum for any spin (except spin zero) in any even dimension d. All known free equations for non-zero spin for massless fields belong to this type of equations. Requiring Hermiticity1 of the equations of motion operator as well as irreduci...

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 ...

ar X iv : h ep - t h / 93 11 13 8 v 1 2 3 N ov 1 99 3 Lattice models and N = 2 supersymmetry

We review the construction of exactly solvable lattice models whose continuum limits are N = 2 supersymmetric models. Both critical and off-critical models are discussed. The approach we take is to first find lattice models with natural topological sectors, and then identify the continuum limits of these sectors with topologically twisted N = 2 supersymmetric field theories. From this, we then ...

Editorial note Volume 6 Issue 3