Dirac operators lie at the heart of both mathematical physics and differential geometry, offering a unifying framework for the treatment of quantum mechanical systems and geometrical invariants. Their ...

Proceedings of the American Mathematical Society, Vol. 32, No. 2 (Apr., 1972), pp. 484-490 (7 pages) In this paper is presented a theory of unbounded operators which admit spectral distributions. The ...

Let T = H + iK be hyponormal and 𝜑 be a strictly monotone increasing continuous function on σ(H). We define $\tilde{\varphi}(T)$ by $\tilde{\varphi}(T)=\varphi (H)+iK$. In this paper, we show that if ...

Spectral problems in boundary value problems constitute a fundamental area of applied mathematics and mathematical physics, where the focus lies on determining eigenvalues and corresponding ...