4 problems

Let $\Sigma\subset \mathbb{R}^d$ be a compact set that is not a removable set for $\Delta$ in $L^2(\mathbb{R}^d)$. A self-adjoint extension of…

Point-spectrum conjecture. One has $\alpha\in\sigma_p(\widetilde A)$ if and only if either there exists a nontrivial element $y_0$ such that

Let ${\bf L}^n_0$, with $n\in\mathbb{N}$, be a self-adjoint extension of the minimal operator $L^n_{\scriptstyle \text{min}}$ on $L^2[(a,b),w]$, with deficiency indices $(m,m)$ whe…

Complete Lagrangian boundary-condition conjecture. The boundary condition