4 problems

Let $\mathcal{A}$ be a unital C$^*$-algebra. A MASA is a maximal abelian C$^*$-subalgebra of $\mathcal{A}$, and a W$^*$-algebra is a C$^*$-algebra admitting a Banach-space predual.…

The 2-quastrace conjecture. Every $2$-quasitrace on a unital C$^*$-algebra is a trace.

Let $A$ and $D$ be separable and unital $\mathrm{C}^*$-algebras, with $D$ strongly self-absorbing. For a $\mathrm{C}^*$-algebra $B$, write $\mathcal Q(B)=\mathcal M(B)/B$ for its c…

Let $S\subset\mathbb{N}^{\times}\setminus\{1\}$ be a family of relatively prime numbers with $\lvert S\rvert\geq 2$. Let $\mathcal{A}_S$ be the torsion subalgebra associated to $S$…