Past exam of the mathematics course of the University of Cambridge / 2023 / iii / Paper 107 / 2 / Solution

Uniform ellipticity means that there is $\lambda >0$ such that the symmetric part of the principal coefficient matrix satisfiesfor every $x\in \Omega$ and $\xi \in {\mathbb{R}}^n$. This is the defining coercive bound for a uniformly elliptic operator.