  Hypergraph categories are symmetric monoidal categories where each object is
equipped with a special commutative Frobenius algebra (SCFA). Dagger-hypergraph
categories are the same, but with dagger-symmetric monoidal categories and
dagger-SCFAs. In this paper, we show that finite matrices over a field K of
characteristic 0 are complete for hypergraph categories, and that finite
matrices where K has a non-trivial involution are complete for
dagger-hypergraph categories.
