André Chastel (1912-1990)

A conjecture of Yves André . ∗

The introduction to [2] (and references contained therein) contains a comprehensive exposition of terminology and notations relative to this conjecture. Since we use the same terminology and notations, we do not reproduce them here. The introduction to [2] also contains an exposition of results on this conjecture obtained before the article [3] came out. In this article we prove the following t...

François Bach and André Herbelin

Reals which Compute Little André

We investigate combinatorial lowness properties of sets of natural numbers (reals). The real A is super-low if A′ ≤tt ∅′, and A is jump-traceable if the values of {e}A(e) can be effectively approximated in a sense to be specified. We investigate those properties, in particular showing that super-lowness and jump-traceability coincide within the r.e. sets but none of the properties implies the o...

Michael Abercrombie (1912-1979).

Richard Doll 1912–2005

the differences of organic production. However, the exclusion of synthetic pesticides and fertilizers from organic systems is fundamental. Given this, the authors asked, why did the magnitude of differences in species density and abundance vary so much between the different groups they looked at? One factor may be the differential impacts of timing and special scales on the colonization traits ...