On null 3-hypergraphs

Given a 3-uniform hypergraph H consisting of set V vertices, and T?V3 triples, null labelling is an assignment ±1 to the triples such that each vertex contained in equal number labelled +1 ?1. Thus, signed degree zero. A necessary condition for every even. The Null Labelling Problem determine whether has labelling. It proved this problem NP-complete. Computer enumerations suggest most hypergraphs which satisfy do have Some constructions are given produce satisfying condition, but not self complementary 3-hypergraph with property also constructed.