Algebraically closed groups

Strong boundedness and algebraically closed groups

Let G be a non-trivial algebraically closed group and X be a subset of G generating G in infinitely many steps. We give a construction of a binary tree associated with (G,X). Using this we show that if G is ω1-existentially closed then it is strongly bounded.

Pseudo Algebraically Closed Extensions

Imaginaries in algebraically closed valued fields

These notes are intended to accompany the tutorial series ‘Model theory of algebraically closed valued fields’ in the Workshop ‘An introduction to recent applications of model theory’, Cambridge March 29–April 8, 2005. They do not contain any new results, except for a slightly new method of exposition, due to Lippel, of parts of the proof of elimination of imaginaries, in Sections 8 and 9. They...

McKay correspondence over non algebraically closed fields

The classical McKay correspondence for finite subgroups G of SL(2,C) gives a bijection between isomorphism classes of nontrivial irreducible representations of G and irreducible components of the exceptional divisor in the minimal resolution of the quotient singularity A2C/G. Over non algebraically closed fields K there may exist representations irreducible over K which split over K. The same i...

Deenability of Geometric Properties in Algebraically Closed Fields Deenability of Geometric Properties in Algebraically Closed Fields Deenability of Geometric Properties in Algebraically Closed Fields

We prove that there exists no sentence F of the language of rings with an extra binary predicat I satisfying the following property for every de nable set X C X is connected if and only if C X j F where I is interpreted by X We conjecture that the same result holds for the closed subsets of C We prove some results motivated by this conjecture