Abstract
Using numerical simulations and the Sheth-Tormen approximation we study the mass function of dark matter halos in voids. We find that the void mass function is significantly lower and its shape is different than that of the field halos. We predict that in the standard LCDM model a void with radius 10h-1Mpc should have 50 halos with circular velocity v[c] > 50 km/s and 600 halos with v[c] > 20 km/s.
