3 problems

Let $A,B\subseteq\mathbb{R}^n$ be bounded measurable sets, and let $\Gamma$ be a set of isometries of $\mathbb{R}^n$. The sets $A$ and $B$ are $\Gamma$-equidecomposable if they adm…

Let $\Gamma$ be a discrete group acting concretely on a measure space $X=(X,\mathcal{X},\mu)$, and let $K$ be a compact Hausdorff abelian group. A concrete $K_{\mathcal{B}a}$-value…

Ergodic coboundary non-degeneracy conjecture. Then $\delta=0$ $\nu$-almost everywhere.