We analyse the production and propagation of pions and kaons in heavy-ion
reactions from 0.8 -- 1.8~A⋅GeV within a coupled channel transport
approach including the kaon production channels BB→K+YN,πB→K+Y,BB→NNKKˉ,πB→NKKˉ,K+B→K+B and ππ→KKˉ. Assuming the hyperon selfenergy to be 2/3 of the nucleon selfenergy
we find that all inclusive experimental K+ spectra at SIS energies can be
reproduced reasonably well without any selfenergies for the kaons although a
slightly repulsive kaon potential cannot be excluded by the present data on
kaon spectra and flow.Comment: 19 pages, LaTeX, including 8 postscript figures, to appear in Nucl.
Phys.