arXiv subjects
Publications and source records attributed to L. Palacios.
We present the results of the computation of a twisting type N solution to vacuum Einstein equations following an iterative approach. Our results show that the higher order terms fail to provide a full exact solution with non-vanishing twist. Nevertheless, our fourth-order solution still represents a regular and twisting type N solution.
We are presenting a general solution to the classical Einstein--Maxwell--dilaton--axion equations starting from a metric of type--D. Namely, this stringy solution is the result of a transformation on a general vacuum type--D solution to the Einstein's equations which was studied in detail some years ago.
We present a general argument for the construction of BRST charges of the `non-critical' $\W_{2,4}$, $\W_{2,5}$, $\W_{2,6}$, and $\W_{2,8}$ strings. This evidences the existence of BRST charges for a kind of soft-type algebras which can be constructed from two copies of quantum $\W_{2,s}$ algebras, (s=3,4,5,6,8).
Many $W$-algebras (e.g. the $W_N$ algebras) are consistent for all values of the central charge except for a discrete set of exceptional values. We show that such algebras can be contracted to new consistent degenerate algebras at these exceptional values of the central charge.