gap> K:=ContractibleGcomplex("SL(3,Z)a");;
gap> R:=FreeGResolution(K,2);;
gap> P:=PresentationOfResolution(R);;
gap> G:=P.freeGroup/P.relators;
&lt;fp group on the generators [ x, y, z ]>
gap> GG:=SimplifiedFpGroup(G);
&lt;fp group on the generators [ x, y, z ]>
gap> RelatorsOfFpGroup(GG);
[ x^2, z^2, y^4, (x*y)^3, x*y*z*x*y^2*x*z*y^-1, 
  x*y*z*y^-1*x*y*x*y^-1*x*z*y*(x*y^-1)^2*x*z*y, 
  y*x*y^-1*x*y*x*y^-2*x*(y*z)^2*y^-1*z*y*x*y^-1*x*(y*z)^2*y^-1*z*y^-1*x*y ]
gap> gens:=R!.elts{P.gens};
[ [ [ 1, 0, 0 ], [ 1, -1, 0 ], [ -4, 0, -1 ] ], 
  [ [ 2, 1, 1 ], [ 1, 1, 1 ], [ -3, -3, -2 ] ], 
  [ [ 0, 1, 0 ], [ 1, 0, 0 ], [ -2, -2, -1 ] ] ]
