Abstract We define and study Toeplitz operators on the Fréchet space of all holomorphic functions finitely connected domains in Riemann sphere. completely characterize Fredholm, semi-Fredholm invertible belonging to this class. As a result, we obtain characterization these classes unit disk case. motivation formulate analyze Riemann–Hilbert problem which consider.

The purpose of this paper is to introduce and study a new class operators that we call pseudogeneralized invertible operators. This includes both the generalized Drazin Some results connected with ascent essential are also obtained for class. relationship between pseudo-generalized operators, semi-Fredholm explored.

Parasupersymmetric quantum mechanics is exploited to introduce a topological invariant associated with a pair of parameter dependent Fredholm (respectively elliptic diierential) operators satisfying two compatibility conditions. An explicit algebraic expression for this topological invariant is provided. The latter identiies the parasupersymmetric topological invariant with the sum of the analy...

Parasupersymmetric quantum mechanics is exploited to introduce a topological invariant associated with a pair of parameter dependent Fredholm (respectively elliptic differential) operators satisfying two compatibility conditions. An explicit algebraic expression for this topological invariant is provided. The latter identifies the parasupersymmetric topological invariant with the sum of the ana...

We explore the relationship between the Evans function, transmission coefficient and Fredholm determinant for systems of first-order linear differential operators on the real line. The applications we have in mind include linear stability problems associated with travelling wave solutions to nonlinear partial differential equations, for example reaction-diffusion or solitary wave equations. The...

1. Compact operators on Banach spaces 2. Appendix: total boundedness and Arzela-Ascoli [Fredholm 1900/1903] treated compact operators as limiting cases of finite-rank operators. [1] [Riesz 1917] defined and made direct use of the compactness condition, more apt for Banach spaces. See [Riesz-Nagy 1952] for extensive discussion in the Hilbert-space situation, and many references to original paper...

In [EE1] and [EE2] we presented the solution to the index problem for a natural class of hypoelliptic differential operators on compact contact manifolds. The methods developed to deal with that problem have wider applicability to the index theory of hypoelliptic Fredholm operators. As an example of the power of the proof techniques we present here a new proof of a little known index theorem of...