title: Singularity spectrum
text: # Singularity spectrum
  
  The singularity spectrum is a function used in multifractal analysis to describe the fractal dimension of a subset of points of a function belonging to a group of points that have the same Hölder exponent. Intuitively, the singularity spectrum gives a value for how "fractal" a set of points are in a function.
  
  More formally, the singularity spectrum $D(\alpha )$ of a function, $f(x)$, is defined as:
  
      $D(\alpha )=D_{F}\{x,\alpha (x)=\alpha \}$
  
  Where $\alpha (x)$ is the function describing the Hölder exponent, $\alpha (x)$ of $f(x)$ at the point $x$. $D_{F}\{\cdot \}$ is the Hausdorff dimension of a point set.
  
  