v

Set v of ZG-generators for the submodule '

(-1+x)e_a

(-1+y)e_b

(-1+xy)e_c

(-1-y-xy-x²y-yxy-yx²y)e_a+(-1-x-x²-yx-x³-xyx-yx²-x²yx-xyx²-x³yx-x²yx²-yx²yx)e_b+(1+x+y+x²+yx+xyx+x²yx+x³yx)e_c