Low x Behavior of the Isovector Nucleon Polarized Structure Function and the Bjorken Sum Rule

The combination g^p_1(x)-g^n_1(x) is derived from SLAC data on polarized proton and deuteron targets, evaluated at Q²=10 GeV², and compared with the results of SMC experiment. The agreement is satisfactory except for the points at the three lowest x, which have an important role in the SMC evaluation on the L.H.S. of the Bjorken sum rule.