3 problems

Let $D\subseteq\Omega$ be an open set with continuous boundary satisfying the geometric conditions in the semi-uniform stability setup of ${}^{\text{su}}$, and let $\1_D$ denote mu…

Let $\mathbb{M}_n$ denote the space of $n$-by-$n$ matrices, and let unitary equivalence have its usual meaning. Finite-dimensional obstruction conjecture. There exists…

Let $A$ be an operator acting on an infinite-dimensional separable Hilbert space $\mathcal{H}$. For a subspace $\mathcal{S}\subset\mathcal{H}$, let $A_{\mathcal{S}}$ denote the cor…