English

Commuting-Square Subfactors and Central Sequences

Operator Algebras 2008-08-20 v1

Abstract

Let M0M1M_0 \subset M_1 be a finite-index infinite-depth hyperfinite II1II_1 subfactor and ω\omega a free ultrafilter of the natural numbers. We show that if this subfactor is constructed from a commuting square then the central sequence inclusion M0ωM1(M0)ωM_0^{\omega} \cap M_1' \subset (M_0)_{\omega} has infinite Pimnser-Popa index. We will also demonstrate this result for certain infinite-depth hyperfinite subfactors coming from groups.

Cite

@article{arxiv.0808.2487,
  title  = {Commuting-Square Subfactors and Central Sequences},
  author = {Richard Burstein},
  journal= {arXiv preprint arXiv:0808.2487},
  year   = {2008}
}

Comments

18 pages

R2 v1 2026-06-21T11:11:40.262Z