# File lib/facets/more/quaternion.rb, line 360
  def - (other)
    if other.kind_of?(Quaternion)
      Quaternion(@re-other.re,@im-other.im,@jm-other.jm,@km-other.km)
    elsif other.kind_of?(Complex)
      Quaternion(@re-other.real,@im-other.image, @jm, @km)
    elsif Complex.generic?(other)
      Quaternion(@re-other.real,@im, @jm, @km)
    else x , y = other.coerce(self); x - y
    end
  end