SPACE reaches arbitrarily high body order with compact equivariant tensor products, dropping the low-order cluster-expansion truncation
The authors introduce SPACE, an architecture that keeps locality, smoothness and symmetry priors while using efficient tensor products in a compact equivariant representation to let body order grow to the number of atoms in the receptive field, so it does not assume low-order truncation of the body-ordered series; the work is presented as an architectural demonstration that the design space of equivariant architectures still has poorly explored regions.