Lower bounds for open charm and beauty contributions to F_2
  On the basis of some peculiar scaling properties of the OPE coefficient functions, we give the lower bounds for F_2^{c\bar{c}} and F_2^{b\bar{b}} independently of the properties of the gluon density function. Predictions for F_2^{b\bar{b}} within reach of HERA are made. 
A.V. Kisselev and V.A. Petrov (IHEP, Protvino)