José Luis Rodríguez

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— In a recent work, the iterative forward–backward (FB) method has been proposed to solve the magnetic field integral equation (MFIE) for smooth one-dimensional (1-D) rough surfaces. This method has proved to be very efficient, converging in a very small number of iterations. Nevertheless, this solution becomes unstable when some obstacle, like a ship or a(More)
A group homomorphism η : H → G is called a localization of H if every Libman showed that a localization of a finite group need not be finite. This is exemplified by a well-known representation A n → SO n−1 (R) of the alternating group A n , which turns out to be a localization for n even and n ≥ 10. Emmanuel Farjoun asked if there is any upper bound in(More)
In this paper we answer negatively a question posed by Libman and Casacuberta about the preservation of perfect groups under localization functors. Indeed, we show that the p-localization of Berrick's and Casacuberta's universal acyclic group is not perfect. We also investigate under which conditions perfectness is preserved: For instance, we show that if(More)
Often a localization functor (in the category of groups) sends a finite simple group to another finite simple group. We study when such a localization also induces a localization between the automorphism groups and between the universal central extensions. As a consequence we exhibit many examples of localizations of finite simple groups which are not(More)
To every variety of groups W one can associate an idempotent radical P W by iterating the verbal subgroup. The basic example is the perfect radical, which is the intersection of the transfinite derived series. We prove that each such radical P W is generated by a single locally free group F , in the sense that, for every group G, the subgroup P W G is(More)
In this paper we generalize the plus-construction given by M. Livernet for algebras over rational differential graded Koszul operads to the framework of admissible operads (the category of algebras over such operads admits a closed model category structure). We follow the modern approach of J. Berrick and C. Casacuberta defining topological(More)