UniversalGBasis(I: IDEAL): LIST of RINGELEM

-- The ideal generated by the 3x3 minors of 3x4 matrix of indeterminates
-- has 96 marked reduced Groebner bases
/**/ Use R ::= QQ[a,b,c,d,e,f,g,h,i,j,k,l];
/**/ I:=ideal(minors(mat([[a,b,c,d],[e,f,g,h],[i,j,k,l]]),3));
/**/ indent(UniversalGBasis(I));
[d*g*j -c*h*j -d*f*k +b*h*k +c*f*l -b*g*l,
 d*g*i -c*h*i -d*e*k +a*h*k +c*e*l -a*g*l,
 d*f*i -b*h*i -d*e*j +a*h*j +b*e*l -a*f*l,
 c*f*i -b*g*i -c*e*j +a*g*j +b*e*k -a*f*k
]