  Reggeon field theory (RFT), originally developed in the context of high
energy diffraction scattering, has a much wider applicability, describing, for
example, the universal critical behavior of stochastic population models as
well as probabilistic geometric problems such as directed percolation. In 1975
Suranyi and others developed cut RFT, which can incorporate the cutting rules
of Abramovskii, Gribov and Kancheli for how each diagram contributes to
inclusive cross-sections. In this note we describe the corresponding
probabilistic interpretations of cut RFT: as a population model of two
genotypes, which can reproduce both asexually and sexually; and as a kind of
bicolor directed percolation problem. In both cases the AGK rules correspond to
simple limiting cases of these problems.
