David Blanc

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We review Quillen's concept of a model category as the proper setting for deening derived functors in non-abelian settings, explain how one can transport a model structure from one category to another by mean of adjoint functors (under suitable assumptions), and deene such structures for categories of cosimplicial coalgebras. 1. Introduction Model(More)
We define a sequence of purely algebraic invariants – namely, classes in the Quillen cohomology of the Π-algebra π * X – for distinguishing between different homotopy types of spaces. Another sequence of such cohomology classes allows one to decide whether a given abstract Π-algebra can be realized as the homotopy Π-algebra of a space.
Given a suitable functor T : C → D between model categories, we define a long exact sequence relating the homotopy groups of any X ∈ C with those of T X, and use this to describe an obstruction theory for lifting an object G ∈ D to C. Examples include finding spaces with given homology or homotopy groups. A number of fundamental problems in algebraic(More)
We present a simple model to estimate the subsidy cost embedded in a global feed-in tariff (GFIT) to simultaneously stimulate electrification and the take-up of renewable energy sources for electricity generation in developing countries. The GFIT would subsidize developing countries for investments they make in generation capacity for renewable electricity(More)