12 citations · 50 across the 28 of their papers we have counts for
7 papers · 1 filter
Uniform subellipticity
A. F. M. ter Elst, Derek W. Robinson
We establish two global subellipticity properties of positive symmetric second-order partial differential operators on $L_2(\Ri^d)$. First, if $m \in \Ni$ then we consider operator…
Analysis of degenerate elliptic operators of Grushin type
Derek W. Robinson, Adam Sikora
We analyze degenerate, second-order, elliptic operators in divergence form on . We assume the coefficients are real symmetric and $a_1H_δ\geq…
Contraction semigroups on
Derek W. Robinson, A. F. M. ter Elst
If is a non-degenerate vector field on and we examine conditions for the closure of to generate a continuous semigroup on which extends to the…
Degenerate elliptic operators: capacity, flux and separation
Derek W. Robinson, Adam Sikora
Let be the semigroup generated on $L_2(\Ri^d)$ by a self-adjoint, second-order, divergence-form, elliptic operator with Lipschitz continuous coefficients.…
Small time asymptotics of diffusion processes
A. F. M. ter Elst, Derek W. Robinson, Adam Sikora
We establish the short-time asymptotic behaviour of the Markovian semigroups associated with strongly local Dirichlet forms under very general hypotheses. Our results apply to a wi…
Dirichlet forms and degenerate elliptic operators
A. F. M. ter Elst, Derek W. Robinson, Adam Sikora +1
It is shown that the theory of real symmetric second-order elliptic operators in divergence form on $\Ri^d$ can be formulated in terms of a regular strongly local Dirichlet form ir…