This first order system of partial differential equations has the following properties.

She is mainly known for her work on partial differential equations.

He made contribution to the development of partial differential equations.

They were among the first partial differential equations to be written down.

Let us consider an example of a first order partial differential equation.

He returned to work on partial differential equations from about 1950.

Its solution opened the road to important results in the new theory of partial differential equations.

This has had a great effect on the theory of partial differential equations.

This issue is especially important in the solution of partial differential equations.

It is useful in the study of partial differential equations.