# Category:Elliptic

This category contains all control problems which are governed by an elliptic partial differential equation.

A second order linear partial differential equation can be written as $\sum^n_{i,j=1} a_{ij} \frac{\partial^2u}{\partial x_i \partial x_j} +\, \text{lower-order terms} = 0$.

If the matrix $A=(a_{ij})_{ij}$ is positive or negative definite, the partial differential equation is called elliptic.

An example is the Poisson's equation: $-\Delta u = f$, where $\Delta$ denotes the Laplace operator, $u$ is the unknown, and the function $f$ is given.

## Pages in category "Elliptic"

The following 2 pages are in this category, out of 2 total.