6. Glossary

Integral equation

An equation where the unknown solution function appears in an integral.

Fredholm integral operator

The integral contains the unknown solution function and the integrand is integrable, often continuous.

Volterra integral equation

The integral operator has a time dependence, showing the unknown solution at a current time is dependent on the past history of the solution.

Ill-posed problem

The solution is very unstable with regard to small changes in the data of the problem.

Principal value integral

An integral that need not be absolutely integrable, but exists with a certain sense of averaging. These occur in Cauchy...