[FOM] Workshop Definability in Number Theory

[Jeroen Demeyer]

We announce the workshop "Definability in Number Theory" at Ghent
University (Belgium) from 30 August to 4 September.

The main topic of the workshop is studying which sets and structures
can be defined or interpreted in the existential or first-order theory
of rings and fields.  We are particularly interested in rings and fields
which play a role in number theory.  Questions about definability have
important applications for (un)decidability.  For example, the negative
answer to Hilbert's Tenth Problem followed from the fact that all
recursively enumerable sets in Z are existentially definable over Z.
Another example is the fact that Z is existentially definable inside
R(t), with the consequence that diophantine equations over R(t) are
undecidable.

More information can be found at the website http://cage.ugent.be/dnt

Jeroen Demeyer