3 problems

Let $A$ be a UHF algebra and let $(\sigma_t)_{t\in\mathbb R}$ be a flow on $A$, that is, a point-norm continuous one-parameter group of automorphisms of $A$. Powers–Sakai conjectur…

Let $G$ be a countable discrete group with a reasonable finiteness condition for its cohomology, and let $\mathfrak{P}$ be a set of prime numbers. The UHF obstruction realization c…

Let $G$ be a countable discrete group, and let $c\fundin H^3(G,\mathbb{T})$ have non-zero finite order $r$. A finite-order obstruction realization conjecture asserts that $c$ is re…