# Solutions to dilation equations
**Source**: https://www.maths.tcd.ie/report_series/abstracts/tcdm0111.html
**Parent**: https://www.maths.tcd.ie/research/papers/
**Solutions to dilation equations**
We develop a general technique which is applied to classify all
*L2* solutions of the Haar dilation equation.
This leads to a result
characterising operators which commute with shifts and dilations.
We also present a new tool for studying compactly-supported solutions
and derive several interesting results concerning refinable
characteristic functions, 2- and 3-refinable functions, smoothness
and boundedness.
Finally we present a few shorter results: demonstrating how to find
polynomial solutions to dilation equations, showing how to combine
dilation equations and their solutions, and determining when a
self-affine tile can be a parallelepiped.