/* presentation on standard generators for M12 */ PresentationM12 := function (G : UserGenerators := [], Projective := false) Fct := Projective select ProjectiveOrder else Order; if #UserGenerators eq 0 then UserGenerators := [G.i : i in [1..Ngens (G)]]; end if; if #UserGenerators ne 2 then "Require 2 user generators"; return false; end if; a := UserGenerators[1]; b := UserGenerators[2]; return Fct (a) eq 2 and Fct (b) eq 3 and Fct (a * b) eq 11 and Fct ((a,b)) eq 6 and Fct (a*b*a*b*a*b^-1) eq 6; end function;