# File lib/classifier/lsi.rb, line 155
    def highest_relative_content( max_chunks=10 )
       return [] if needs_rebuild?
       
       avg_density = Hash.new
       @items.each_key { |x| avg_density[x] = proximity_array_for_content(x).inject(0.0) { |x,y| x + y[1]} }
       
       avg_density.keys.sort_by { |x| avg_density[x] }.reverse[0..max_chunks-1].map
    end