  We study the half advanced and half retarded Wheeler Green function and its
relation to Feynman propagators. First for massless equation. Then, for
Klein-Gordon equations with arbitrary mass parameters; real, imaginary or
complex. In all cases the Wheeler propagator lacks an on-shell free
propagation. The Wheeler function has support inside the light-cone (whatever
the mass). The associated vacuum is symmetric with respect to annihilation and
creation operators.
