As far as I understand, the RG theory, or functional RG theory is a mathematical tool for moving in the "scale dimension". The tool can be used for calculation of Feigenbaums constant (e.g. [mentioned here][1]). Can the theory be given a simple example of how to move one "step" in the "scale dimension" ?


  [1]: http://mathworld.wolfram.com/FeigenbaumConstant.html