Structures of small closed non-orientable 3-manifold triangulations

A census is presented of all closed non-orientable 3-manifold triangulations formed from at most seven tetrahedra satisfying the additional constraints of minimality and P-2-irreducibility. The eight different 3-manifolds represented by these 41 different triangulations are identifi.ed and described in detail, with particular attention paid to the recurring combinatorial structures that are shared amongst the different triangulations. Using these recurring structures, the resulting triangulations are generalised to infinite families that allow similar triangulations of additional 3-manifolds to be formed.