5 citations · 26 across the 16 of their papers we have counts for
18 papers
Elliptic systems generating a positive semigroup are decoupled
Wolfgang Arendt, A. F. M. ter Elst, Manfred Sauter
We show that the semigroup associated to a second-order elliptic system is positive if and only if the differential equations are essentially decoupled and the coefficients are rea…
The Generalized Birman-Schwinger Principle
J. Behrndt, A. F. M. ter Elst, F. Gesztesy
We prove a generalized Birman-Schwinger principle in the non-self-adjoint context. In particular, we provide a detailed discussion of geometric and algebraic multiplicities of eige…
On the numerical range of sectorial forms
Antonius Frederik Maria ter Elst, Joachim Rehberg, Alexander Linke
We provide a sharp and optimal generic bound for the angle of the sectorial form associated to a non-symmetric second-order elliptic differential operator with various boundary con…
Hölder kernel estimates for Robin operators and Dirichlet-to-Neumann operators
A. F. M. ter Elst, M. F. Wong
Consider the elliptic operator \[ A = - \sum_{k,l=1}^d \partial_k \, c_{kl} \, \partial_l + \sum_{k=1}^d a_k \, \partial_k - \sum_{k=1}^d \partial_k \, b_k + a_0 \] on a bounded co…
Jordan chains of elliptic partial differential operators and Dirichlet-to-Neumann maps
J. Behrndt, A. F. M. ter Elst
Let be a bounded open set with Lipschitz boundary . It will be shown that the Jordan chains of m-sectorial second-order elliptic partial differential operat…
The Dirichlet problem without the maximum principle
W. Arendt, A. F. M. ter Elst
Consider the Dirichlet problem with respect to an elliptic operator \[ A = - \sum_{k,l=1}^d \partial_k \, a_{kl} \, \partial_l - \sum_{k=1}^d \partial_k \, b_k + \sum_{k=1}^d c_k \…