gap> K:=ContractibleGcomplex("SL(3,Z)s");;
gap> R:=FreeGResolution(K,3);;
gap> P:=PresentationOfResolution(R);;
gap> G:=P.freeGroup/P.relators;
&lt;fp group on the generators [ f, g, h, k, m, n, p, q, r, s, t, u, v, w, x, y, 
  z ]>
gap> GG:=SimplifiedFpGroup(G);
&lt;fp group on the generators [ h, m ]>
gap> RelatorsOfFpGroup(GG);
[ m^3, h^6, (h*m^-1)^4, (m^-1*h)^4, (m^-1*h^3)^2*m^-1*h^-3, (h*m^-1*h)^4, 
  (h*m^-1)^2*(h^-1*m*h^-1)^2*(m^-1*h)^2*m, 
  m^-1*h^-1*m*h^-1*m^-1*h*(m*h^-1)^2*(m^-1*h)^2*h*m^-1*h^-1*m*h^-1, 
  m^-1*(h^-1*m*h^-1)^2*m*h*(m^-1*h^-1*m*h^-1)^2*m^-1*h*m^-1, 
  (h^-1*m^-1*h*m^-1)^2*h^2*m^-1*h*m*h*m^-1*h^-2*m*h^-1*m^-1*h^-1*m, 
  h^-1*m^-1*h^2*m^-1*h*m*h*(m^-1*h^-2)^2*m^-1*h*m*h*m^-1*h^2*m^-1, 
  h*m^-1*h^-1*m*h^-2*m*h*m^-1*h^2*m*h*m^-1*(h^-1*m)^2*h*m^-1*h*m*h, 
  (h^-1*m)^2*h*m*h^-1*m^-1*h^-1*m*h^-2*(m*h^-1*m*h)^2*m^-1*h*m^-1, 
  m^-1*h^-1*m*h^-2*m^-1*(h*m^-1*h)^2*m^-1*h^-2*m*h*m^-1*h^-1*m*h^-2*m*h*m^-1*(\
h^2*m^-1*h)^2*(m*h^-1)^2*h^-1*m*h^2*(h*m^-1)^3*h^-2 ]
                   
gap> gens:=R!.elts{P.gens{[3,5]}};
[ [ [ 1, 0, 0 ], [ 0, 0, -1 ], [ 0, 1, 1 ] ], 
  [ [ 0, 0, 1 ], [ 1, 0, 0 ], [ 0, 1, 0 ] ] ]
gap> List(gens,Order);
[ 6, 3 ]
