Title On a geometry of Ivanov and Shpectorov for the O'Nan sporadic simple group Authors Francis Buekenhout and Dimitri Leemans Reference J. Combin. Theory Ser. A 85(1999), no. 2, 148-164. Math. Reviews 2000a:51014 Zentralblatt 930.20014 Abstract We show, for the O'Nan sporadic simple group, that there is no RWPRI and (IP)_2 geometry of rank greater than 6 with a subgroup forming the geometry isomorphic to M_11 and that there is no RWPRI and (IP)_2 geometry of rank greater than 5 with a subgroup forming the geometry isomorphic to J_1. The results rely partially on computer algebra.