  The differential production cross sections of K^+ and K^- mesons have been
measured at the ITEP proton synchrotron in p+Be, p+Cu collisions under lab
angle of 10.5^0, respectively, at 1.7 and 2.25, 2.4 GeV beam energies. A
detailed comparison of these data with the results of calculations within an
appropriate folding model for incoherent primary proton-nucleon, secondary
pion-nucleon kaon and antikaon production processes and processes associated
with the creation of antikaons via the decay of intermediate phi mesons is
given. We show that the strangeness exchange process YN->NNK^- gives a small
contribution to the antikaon yield in the kinematics of the performed
experiment. We argue that in the case when antikaon production processes are
dominated by the channels with KK^- in the final state, the cross sections of
the corresponding reactions are weakly influenced by the in-medium kaon and
antikaon mean fields.
