Most of the authors of research papers in compressed sensing use n-widths and kolmogorov's entropy extensively which are a kind of hard for me to understand. Any suggestion on books or expository articles about these will be highly appreciated.

Most of the authors of research papers in compressed sensing use n-widths and Kolmogorov's entropy extensively, which are kind of hard for me to understand. Any suggestion on books or expository articles about these will be highly appreciated.