The sporadic simple group F2 known as Fischer's Baby Monster acts flag-transitively on a rank 5 P-geometry G(F2). P-geometries are geometries with string diagrams, all of whose nonempty edges except one are projective planes of order 2 and one terminal edge is the geometry of the Petersen graph. Let AC be a flag-transitive P-geometry of rank 5. Suppose that each proper residue of K is isomorphi...

The collineation groups of even order translation planes which are cubic extensions of flag-transitive planes are determined. 2000 Mathematics Subject Classification. Primary 51E.

Given a flag in each of the vertex-transitive tessellations of the Euclidean plane by regular polygons, we determine the flag stabilizer under the action of the automorphism group of a regular cover. In so doing we give a presentation of these tilings as quotients of regular (infinite) polyhedra.

A con guration is weakly ag transitive if its group of automor phisms acts intransitively on ags but the group of all automorphisms and anti automorphisms acts transitively on ags It is shown that weakly ag transitive con gurations are in one to one correspondence with bipartite  arc transitive graphs of girth not less than Sev eral in nite families of weakly ag transitive con gurations are gi...

A connguration is weakly ag-transitive if its group of automor-phisms acts intransitively on ags but the group of all automorphisms and anti-automorphisms acts transitively on ags. It is shown that weakly ag-transitive conngurations are in one-to-one correspondence with bipartite 1 2-arc-transitive graphs of girth not less than 6. Several innnite families of weakly ag-transitive conngurations a...

Let Z = G/Q be a complex flag manifold. The compact real form Gu of G is transitive on Z. If G0 is a noncompact real form, such transitivity is rare but occasionally happens. Here we work out a complete list of Lie subgroups of G transitive on Z and pick out the cases that are noncompact

A 2&(v, k, 1) design D=(P, L) is a system consisting of a finite set P of v points and a collection L of a k-subset of P, called lines, such that each 2-subset of P is contained in precisely one line. We shall always assume that 2<k<v. Let G Aut(D) be a group of automorphisms of a 2&(v, k, 1) design D. The group G is said to be line-transitive (line-primitive, respectively) on D if G is transit...