Essential spectra of elliptic partial differential equations

Essential Spectra of Elliptic Partial Differential Equations

Let A be a closed, densely defined operator in a Banach space X. There are several definitions of the "essential" spectrum of A (cf. [ l ] , [2]). According to Wolf [3], [4] it is the complement in the complex plane of the $-set of A. The $-set $A of A is the set of points X for which (a) a(A — X), the dimension of the null space of A — X, is finite (b) R(A —X), the range of A —X, is closed (c)...

Lecture Notes on Elliptic Partial Differential Equations

On the Construction of Discretizations of Elliptic Partial Differential Equations

Dedicated to Gerry Ladas on the occasion of his 60th Birthday Algorithmic aspects of a class of nite element collocation methods for the approximate numerical solution of elliptic partial diierential equations are described. Locally, for each nite element, the approximate solution is a polynomial. Polynomials corresponding to adjacent nite elements need not match continuously, but their values ...

On the Solutions of Quasi-linear Elliptic Partial Differential Equations*

The literature concerning these equations being very extensive, we shall not attempt to give a complete list of references. The starting point for many more modern researches has been the work of S. Bernstein,f who was the first to prove the analyticity of the solutions of the general equation with analytic and who was able to obtain a priori bounds for the second and higher derivatives of ...

Schur complement preconditioning for elliptic systems of partial differential equations

S hur omplement pre onditioning for ellipti systems of partial di erential equations D. Loghin and A. J. Wathen One su essful approa h in the design of solution methods for saddle-point problems requires the eÆ ient solution of the asso iated S hur omplement problem ([26℄, [19℄). In the ase of problems arising from partial di erential equations the fa torization of the symbol of the operator an...