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The cohomological equation and cyclic cocycles for renormalizable minimal Cantor systems

Rodrigo Treviño

Abstract

For typical properly ordered and minimal Bratteli diagrams $(B,\leq_r)$, it is shown that there are finitely many invariant distributions $\mathcal{D}_i$ which are the only obstructions to solving the cohomological equation $f = u-u\circ φ$ for the corresponding adic transformation $φ:X_B\rightarrow X_B$ and for $α$-Hölder $f$ with $α$ large enough. These invariant distributions are then used to define cyclic cocycles, a.k.a. traces $τ:K_0(\mathcal{A}_φ)\rightarrow \mathbb{R}$ for the crossed product algebra $\mathcal{A}_φ$.

The cohomological equation and cyclic cocycles for renormalizable minimal Cantor systems

Abstract

For typical properly ordered and minimal Bratteli diagrams , it is shown that there are finitely many invariant distributions which are the only obstructions to solving the cohomological equation for the corresponding adic transformation and for -Hölder with large enough. These invariant distributions are then used to define cyclic cocycles, a.k.a. traces for the crossed product algebra .

Paper Structure

This paper contains 10 sections, 12 theorems, 106 equations.

Key Result

Theorem 1.1

Let $\mu$ be a minimal, proper, $\sigma$-invariant ergodic probability measure on $\mathcal{O}_\beth$ satisfying Condition cond:1. Then there is a $d_\mu\in\mathbb{N}$ such that for $\mu$-almost every $x = (B,\leq_r)\in \mathcal{O}_\beth$, for any $\alpha>2$ there are $d_\mu$ obstructions to solving

Theorems & Definitions (24)

  • Theorem 1.1
  • Theorem 1.2
  • Definition 3.1
  • Definition 3.2
  • Theorem 3.1: Kesten-Furstenberg Theorem
  • Proposition 4.1
  • proof
  • Proposition 4.2
  • proof
  • Definition 5.1
  • ...and 14 more