Absolute real root separation
  While the separation (the minimal nonzero distance) between roots of a polynomial is a classical topic, its absolute counterpart (the minimal nonzero distance between their absolute values) does not seem to have been studied much. We present the general context and give tight bounds for the case of real roots. 
Yann Bugeaud, Andrej Dujella, Tomislav Pejkovic, Bruno Salvy
math.NT