  We consider semi-inclusive unpolarized DIS for the production of charged
Kaons and the different possibilities, both in LO and NLO, to test the
conventionally used assumptions s-\bar s=0, \Delta s-\Delta \bar s=0 and
D_d^{K+ - K-}=0. The considered tests have the advantage that they do not
require any knowledge of the fragmentation functions.
