/*
Realisation of the presentations in L217P1 and L217P1a as permutation
on 18 points.
Generators are x and y and they are standard generators for the group (L2(17)).
Acting on the projective line PG1(17), they are:
  x: \eta -> -1 / \eta,
  y: \eta -> \eta / (\eta - 1),
 xy: \eta -> \eta + 1.
*/

G<x,y>:=PermutationGroup<18|
(1,16)(2,8)(3,11)(5,10)(6,14)(7,12)(9,15)(17,18),
(1,17,18)(2,9,16)(3,12,8)(4,5,11)(6,15,10)(7,13,14)
>;