COMPLETE O(ALPHA) QED CORRECTIONS TO THE PROCESS EP-]EX IN MIXED VARIABLES

The complete set of O(alpha) QED corrections with soft photon exponentiation to the process ep --> eX in mixed variables (y = Y-h, Q(2) = Q(1);(2) calculated in the quark-parton model, including the lepton-quark interference and the quarkonic corrections which were unknown so far. The interference corrections amount to a few percent or less and become negligible at small x. The leading logarithmic terms proportional to 1n(Q(2)/m(q)(2)) from radiation off quarks are discussed and the non-logarithmic quarkonic corrections are found to be negligible for almost all experimentally accessible x and y.