The wrong signature fixed pole in inclusive electroproduction and photoproduction

The residues of the third-spectral-function and current-algebra J = 1 wrong-signature fixed poles are calculated at t = 0, and the connexion between them shown, using finite energy sum rules. In addition to the part of the third-spectral-function pole which is singular as t → 0, the part regular at t = 0 is significantly different from zero for 0 ⩽ −q2 ⩽ 1 (GeV/c)2.