In this paper we represent each element of the Janko group J(1) as a p
ermutation on eleven letters from the projective special linear group
L(2)(11), followed by a word of length at most four in the eleven invo
lutory symmetric generators. An algorithm for multiplying elements rep
resented in this way is described, and computer programs which carry o
ut this procedure and others are given in the appendix. (C) 1996 Acade
mic Press Limited