Ample generics in automorphism groups of Boolean powers of simple Mal'cev algebras
Abstract
Let $\mathbf{A}$ be a finite simple Mal'cev algebra, such as for example a finite simple group, module, ring, associative or Lie algebra, loop or quasigroup.
We show that the automorphism group of a filtered Boolean power of continuous functions from the Cantor space $2^\omega$ to $\mathbf{A}$ has ample generics.
The proof splits into the abelian and non-abelian cases.
In the abelian case, we use a representation by modules and the theory of $n$-systems developed by Kechris and Rosendal.
In the non-abelian case, the proof relies on the decomposition of the automorphism group as a semidirect product of a certain closure of a filtered Boolean power of continuous functions from $2^\omega$ to the automorphism group of $\mathbf{A}$ and the stabiliser of finitely many points in the homeomorphism group $\mathrm{Homeo}\, 2^\omega$.
As an intermediate step, we show that pointwise stabilisers in $\mathrm{Homeo}\, 2^\omega$ have ample generics, which extends Kwiatkowska's result that $\mathrm{Homeo}\, 2^\omega$ has ample generics.
이 뉴스, 어떠셨어요?
한 번의 탭으로 반응을 남겨요 · 로그인 불필요