Mollifiers are smooth functions with special properties used to create smooth approximations of non-smooth functions. They are fundamental tools in mathematical analysis, particularly in the theory of partial differential equations and distribution theory.
A mollifier is typically a smooth function φ with compact support that satisfies:
The convolution of a function f with a mollifier φε produces a smooth approximation of f:
fε(x) = (f ∗ φε)(x) = ∫f(y)φε(x-y)dy
As ε → 0, fε converges to f in various senses depending on the properties of f.
Learn more about mollifiers on Wikipedia.
Applications: