Heavy-quark production in deep-inelastic scattering

We report recent experimental and theoretical progress concerning the heavy-quark electro-production in the context of the ABM11 parton distribution function (PDF) fit. In the updated ABM11 analysis, including the recent combined HERA charm data, the MSbar-values of the c-quark mass m_c(m_c)=1.24 +- 0.03 (exp)\,^{+0.03}_{-0.02}(scale)\,^{+0.00}_{-0.07} (th) and m_c(m_c)=1.15\, +- 0.04 (exp)\,^{+0.04}_{-0.00} (scale) are determined at NNLO and NLO, respectively. The values of m_c obtained are compared to other determinations including the ones based on the various variable-flavor-number (VFN) scheme prescriptions.The VFN scheme uncertainties related to the matching of the 4(5)-flavor PDFs with the 3(4)-flavor ones are discussed.