  Recent experiments have shown that liquid drops on highly deformable
substrates exhibit mutual interactions. This is similar to the Cheerios effect,
the capillary interaction of solid particles at a liquid interface, but now the
roles of solid and liquid are reversed. Here we present a dynamical theory for
this inverted Cheerios effect, taking into account elasticity, capillarity and
the viscoelastic rheology of the substrate. We compute the velocity at which
droplets attract, or repel, as a function of their separation. The theory is
compared to a simplified model in which the viscoelastic dissipation is treated
as a localized force at the contact line. It is found that the two models
differ only at small separation between the droplets, and both of them
accurately describe experimental observations.
