we have to find the order of the group.we have permutation [ (1,3,6),(2,4,12),(7),(8,9,10),(11),(0,5, ∞)] second permutation is [(0, ∞,12),(1,11,6),(2,5,4),(3),(7,10,8),(9)] and third permutation is [(0, ∞),(1,12),(2,6),(7,11),(3,4),(5),(8),(9,10)] ;but we cannot write any symbol for infinity in Gap;please tell us which symbol we should write in GAP; regards