Symmetric topological complexity of projective and lens spaces

For real projective spaces, (a) the Euclidean immersion dimension, (b) the existence of axial maps, and (c) the topological complexity are known to be three facets of the same problem. But when it comes to embedding dimension, the classical work of Berrick, Feder and Gitler leaves a small indeterminacy when trying to identify the existence of Euclidean embeddings of these manifolds with the existence of symmetric axial maps. As an alternative we show that the symmetrized version of (c) captures, in a sharp way, the embedding problem. Extensions to the case of even torsion lens spaces and complex projective spaces are discussed.Comment: Paper reorganized for clarity in expositio

Topological complexity of motion planning in projective product spaces

We study Farber's topological complexity (TC) of Davis' projective product spaces (PPS's). We show that, in many non-trivial instances, the TC of PPS's coming from at least two sphere factors is (much) lower than the dimension of the manifold. This is in high contrast with the known situation for (usual) real projective spaces for which, in fact, the Euclidean immersion dimension and TC are two facets of the same problem. Low TC-values have been observed for infinite families of non-simply connected spaces only for H-spaces, for finite complexes whose fundamental group has cohomological dimension not exceeding 2, and now in this work for infinite families of PPS's. We discuss general bounds for the TC (and the Lusternik-Schnirelmann category) of PPS's, and compute these invariants for specific families of such manifolds. Some of our methods involve the use of an equivariant version of TC. We also give a characterization of the Euclidean immersion dimension of PPS's through generalized concepts of axial maps and, alternatively, non-singular maps. This gives an explicit explanation of the known relationship between the generalized vector field problem and the Euclidean immersion problem for PPS's.Comment: 16 page

The KO*-rings of BT^m, the Davis-Januszkiewicz Spaces and certain toric manifolds

This paper contains an explicit computation of the KO*-ring structure of an m-fold product of CP^{\infty}, the Davis-Januszkiewicz spaces and toric manifolds which have trivial Sq^2-homology.Comment: 34 page

T. A Perry, Art and meaning in Berceo's "Vida de Santa Oria". Yale University Press, New Haven & London, 1968; x + 231 p. (Yale Romanie'Studies, Second Series, 19).

Se reseñó el libro: Art and meaning in Berceo's "Vida de Santa Oria".

The blue foe. The effects of radioactivity in “Ustedes brillan en lo oscuro”, by Liliana Colanzi

En diálogo con Bruno Latour y Carl Schmitt, y a la luz de diversos documentos tanto académicos como organizativos sobre el accidente radiológico de Goiânia, este ensayo postula que el cuento “Ustedes brillan en lo oscuro”, de la boliviana Liliana Colanzi, manifiesta la hostilidad radical de la radiactividad hacia los seres vivos, reivindica a las víctimas del accidente del olvido al que las relegó la política estatal brasileña y visibiliza algunos de los aspectos más conflictivos de la vida en el Antropoceno.In dialogue with Bruno Latour and Carl Schmitt, and in the light of various academic and organizational documents on the radiological accident in Goiânia, this essay postulates that the story “Ustedes brillan en lo oscuro”, by Bolivian writer Liliana Colanzi, manifests the radical hostility of radioactivity toward living beings, advocates the victims of the accident who were relegated to oblivion by Brazilian state policy, and makes visible some of the most conflicting aspects of life in the Anthropocene

<em>Virtud</em> de la retorsión = <em>Nobility</em> of Contortion

Artículo  Virtud de la retorsión</jats:p