The Pomeron structure and diffractive parton distributions
Measurements of the diffractive structure function, $F_2^D$, of the proton at HERA are used to extract the partonic structure of the Pomeron. Regge Factorization is tested and is found to describe well the existing data within the selected kinematic range. The analysis is based on the next to leading order QCD evolution equations. The results obtained from various data sets are compared. An analysis of the uncertainties in determining the parton distributions is provided. The probability of diffraction is calculated using the obtained results.