Proceedings of the Royal Society of Edinburgh: Section A Mathematics

Research Article

Steiner triple systems of order 19 constructed from the Steiner triple system of order 9

Alan R. Princea1

a1 Department of Mathematics, Heriot-Watt University, Edinburgh, Scotland

Synopsis

A standard method of constructing Steiner triple systems of order 19 from the Steiner triple system of order 9 gives rise to 212 different such systems. It is shown that there are just three isomorphism classes amongst these systems. Representatives of each isomorphism class are described and the orders of their automorphism groups are determined.

(Received June 02 1982)

(Revised September 10 1982)