Definition
Local well-posedness of an evolution problem
Local existence, uniqueness in a specified class, and continuous dependence on the data.
An evolution problem is locally well posed near a datum in a data space if there are a time , a neighborhood of , and a specified solution space such that:
- Every datum in has a solution on .
- The solution is unique in the asserted class.
- The map from the datum to its solution in is continuous.
The equation, coefficients, and forcing are held fixed unless the data space explicitly includes them.
Dependence on the chosen spaces
Well-posedness is a statement about both an equation and its data and solution topologies. Existence alone is insufficient. Uniqueness in a smooth class also does not automatically imply uniqueness in every larger weak-solution class.