Dembowski semi-2-spaces (Q794272)

A Dembowski semi-plane is defined to be one of the finite semi-planes constructed by P. Dembowski. A Dembowski semi-i-space (\(i\geq 1)\) is an incidence structure \(J=(P,B,I)\) for which: (i) each element of B is incident with at least \(i+3\) elements of P, and (ii) each i-residual space of J is a Dembowski semi-plane. In ''Dembowski semi-inversive planes'' [European J. Comb. 3, 173-189 (1982; Zbl 0493.51013)], the authors gave the complete classification of all Dembowski semi-1-spaces. Here they classify all Dembowski semi-2-spaces.