Measurement of polarised distribution functions at HERMES

HERMES is a second generation experiment to study the spin structure of the nucleon, in which measurements of the spin-dependent properties of semi-inclusive deep-inelastic lepton scattering are emphasized. By means of the flavor tagging technique, individual spin contributions have been determined directly from spin asymmetries of hadrons with the appropriate flavor content. Moreover, the first experimental results from measurements of single-spin asymmetries for pions and kaons in deep inelastic scattering with transverse target polarisation are presented.