The Automorphism Groups of Steiner Triple Systems Obtained by the Bose Construction

The automorphism group of the Steiner triple system of order v 3 (mod 6), obtained from the Bose construction using any Abelian Group G of order 2s + 1, is determined. The main result is that if G is not isomorphic to Z₃ⁿ × Z₉^m, n 0, m 0, the full automorphism group is isomorphic to Hol(G) × Z₃, where Hol(G) is the Holomorph of G. If G is isomorphic to Z₃ⁿ × Z₉^m, further automorphisms occur, and these are described in full.