Graphical representation of certain moment dualities and application to population models with balancing selection

We investigate dual mechanisms for interacting particle systems. Generalizing an approach of Alkemper and Hutzenthaler in the case of coalescing duals, we show that a simple linear transformation leads to a moment duality of suitably rescaled processes. More precisely, we show how dualities of interacting particle systems of the form H(A,B) = q|A∩B|, A,B ⊂ {0, 1} , q ∈ [−1, 1), are rescaled to yield moment dualities of rescaled processes. We discuss in particular the case q = −1, which explains why certain population models with balancing selection have an annihilating dual process. We also consider different values of q, and answer a question by Alkemper and Hutzenthaler.