Student Experience: Megan Dold, MSc Development Management 2011/12

After completing the Development Management programme in August 2012, I started a full-time job as a communications officer at the Thomson Reuters Foundation in London

Geodesic flow for CAT(0)-groups

We associate to a CAT(0)-space a flow space that can be used as the replacement for the geodesic flow on the sphere tangent bundle of a Riemannian manifold. We use this flow space to prove that CAT(0)-group are transfer reducible over the family of virtually cyclic groups. This result is an important ingredient in our proof of the Farrell-Jones Conjecture for these groups

Semiclassical approximation in Batalin-Vilkovisky formalism

The geometry of supermanifolds provided with $Q$-structure (i.e. with odd vector field $Q$ satisfying $\{ Q,Q\} =0$), $P$-structure (odd symplectic structure ) and $S$-structure (volume element) or with various combinations of these structures is studied. The results are applied to the analysis of Batalin-Vilkovisky approach to the quantization of gauge theories. In particular the semiclassical approximation in this approach is expressed in terms of Reidemeister torsion.Comment: 27 page

The multiplicativity of fixed point invariants

We prove two general factorization theorems for fixed-point invariants of fibrations: one for the Lefschetz number and one for the Reidemeister trace. These theorems imply the familiar multiplicativity results for the Lefschetz and Nielsen numbers of a fibration. Moreover, the proofs of these theorems are essentially formal, taking place in the abstract context of bicategorical traces. This makes generalizations to other contexts straightforward.Comment: 24 pages. v3: final version, to appear in AG

Competition or conflict? Beyond traditional ordo-liberalism

According to the traditional ordo-liberal view of the Freiburg School, the central role of the state in economic affairs is to set up rules that create a competitive order within which private actors have sufficient incentives to coordinate their economic affairs efficiently. Underlying this view is the implicit assumption that, given the right institutional framework, competition within markets is mainly characterized by peaceful and conflict-free rivalry between actors that leads to an optimal allocation of resources. In such a setting, competition may be described as a "record-type" game. This view, however, ignores the possibility that competition itself may very well trigger conflict rather than having an appeasing effect. In this case, competition appears to be a "struggle-type" game in which competitors invest in conflict activities that are not efficiency enhancing but rather resource wasting. Against this background, ordo-liberalism has yet to provide a clear-cut distinction between competition and conflict. In addition, it fails to identify - in a normative way - which institutional and regulatory framework could hamper conflict sensitivity of economic competition, given the harmful effect of conflict on the security of property rights. Our contribution investigates how the ordo-liberal research program needs to be extended when introducing conflict

Cap Products in String Topology

Chas and Sullivan showed that the homology of the free loop space LM of an oriented closed smooth finite dimensional manifold M admits the structure of a Batalin-Vilkovisky (BV) algebra equipped with an associative product called the loop product and a Lie bracket called the loop bracket. We show that the cap product is compatible with the above two products in the loop homology. Namely, the cap product with cohomology classes coming from M via the circle action acts as derivations on loop products as well as on loop brackets. We show that Poisson identities and Jacobi identities hold for the cap product action, extending the BV structure in the loop homology to the one including the cohomology of M. Finally, we describe the cap product in terms of the BV algebra structure in the loop homology.Comment: 19 pages. Revised version 2 with added references, improved exposition, and simplified sign

Jarosite versus Soluble Iron-Sulfate Formation and Their Role in Acid Mine Drainage Formation at the Pan de Azúcar Mine Tailings (Zn-Pb-Ag), NW Argentina

Secondary jarosite and water-soluble iron-sulfate minerals control the composition of acid mine waters formed by the oxidation of sulfide in tailings impoundments at the (Zn-Pb-Ag) Pan de Azúcar mine located in the Pozuelos Lagoon Basin (semi-arid climate) in Northwest (NW) Argentina. In the primary zone of the tailings (9.5 wt % pyrite-marcasite) precipitation of anglesite (PbSO4), wupatkite ((Co,Mg,Ni)Al2(SO4)4) and gypsum retain Pb, Co and Ca, while mainly Fe2+, Zn2+, Al3+, Mg2+, As3+/5+ and Cd2+ migrate downwards, forming a sulfate and metal-rich plume. In the oxidation zone, jarosite (MFe3(TO4)2(OH)6) is the main secondary Fe3+ phase; its most suitable composition is M = K+, Na+, and Pb2+and TO4 = SO42−; AsO42−. During the dry season, iron-sulfate salts precipitate by capillary transport on the tailings and at the foot of DC2 (tailings impoundment DC2) tailings dam where an acid, Fe2+ rich plume outcrops. The most abundant compounds in the acid mine drainage (AMD) are SO42−, Fe2+, Fe3+, Zn2+, Al3+, Mg2+, Cu2+, As3+/5+, Cd2+. These show peak concentrations at the beginning of the wet season, when the soluble salts and jarosite dissolve. The formation of soluble sulfate salts during the dry season and dilution during the wet season conform an annual cycle of rapid metals and acidity transference from the tailings to the downstream environment.Fil: Murray, Jesica María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Kirschbaum, Alicia Matilde. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Dold, Bernhard. Sustainable Mining Research & Consult EIRL; ChileFil: Mendes Guimaraes, Edi. Universidade do Brasilia; BrasilFil: Pannunzio Miner, Elisa Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentin

Condorcet's jury theorem as a rational justification of soft paternalistic consumer policies

The objective of this note is to revisit the meaningfulness of the Condorcet Jury Theorem (CJT) and apply it to the recent debate on liberal paternalism and consumer protection. The CJT con-sists of two parts, (a) stating that a jury of experts is always more competent than a single expert given a certain level of competence, and (b) asserting that for large juries, the collective com-petence approaches infallibility. This note argues that these insights suggest the application of a Condorcet jury voting procedure to the case of nudging boundedly rational consumers. The note proposes a simple calculus for finding an optimal jury size and advocates consumers' meta-preferences as the jury's evaluative dimension for designing soft paternalistic policies