The behaviour of the quark coefficient functions in deep-inelastic scattering
is investigated for large values of the Bjorken variable x. By combining
results of soft-gluon resummation and fixed-order calculations, we determine
the coefficients of the four leading large-x logarithms, alpha_s^k
[{ln(1-x)}^{2k-l}/(1-x)]_+, l = 1, ...4, to all orders in the strong coupling
constant alpha_s. This result includes two more terms for the three-loop
coefficient functions than previously specified in the literature. The effect
of the fifth logarithmic contribution is approximately evaluated. The terms
derived here are required, but also seem to be sufficient, for a reliable
representation of the coefficient functions at large x.Comment: 10 pages, 3 figures, misprints in third line of eq. (15) correcte
