Further illustration of the use of the Frobenius-Schwinger-Dyson equations

The Frobenius-Schwinger-Dyson equations are a rather high-brow abstract nonsense type of equations describing n-point functions of arbitrarily high composite insertions. It is not clear how to solve or even find approximate solutions of these equations in general, but they are worth investigating because (a certain preferred type of) renormalization of composite insertions has been performed in advance: it just remains to find solutions given an action and renormalization conditions. Earlier work in this field involved only Gaussian actions or variable transformations thereof. In this work we illustrate the use of Frobenius-Schwinger-Dyson at a less obviously trivial level, that of the Thirring model.Comment: 10 pages Late

Abelian and derived deformations in the presence of Z-generating geometric helices

For a Grothendieck category C which, via a Z-generating sequence (O(n))_{n in Z}, is equivalent to the category of "quasi-coherent modules" over an associated Z-algebra A, we show that under suitable cohomological conditions "taking quasi-coherent modules" defines an equivalence between linear deformations of A and abelian deformations of C. If (O(n))_{n in Z} is at the same time a geometric helix in the derived category, we show that restricting a (deformed) Z-algebra to a "thread" of objects defines a further equivalence with linear deformations of the associated matrix algebra.Comment: 21 page

No Name, No Game

In an interesting contribution Joppa et al. (2011) revisit some aspects of the taxonomic impediment (Evenhuis 2007; http://www.cbd.int/gti/) and come to the conclusion that, contrary to the generally accepted idea, both the rates of species description and the number of taxonomists have increased exponentially since the 1950’s. Joppa et al. (2011) also note a marked decline in the number of species described per taxonomist which they attribute to the difficulty of finding new species in an ever declining ‘missing species pool’. Therefore, their results might be interpreted that today’s taxonomic workforce is sufficient to describe the remaining (shallow) ‘pool of missing species’. In this contribution, we question if this is indeed the case and propose a solution for speeding up taxonomic descriptions