-- -*- M2-comint -*- hash: 9306279594301915755

i1 : R = QQ[w,x];

i2 : S = QQ[y,z];

i3 : A = arrangement{w, x, w-x}

o3 = {w, x, w - x}

o3 : Hyperplane Arrangement 

i4 : B = arrangement{y, z, y+z}

o4 = {y, z, y + z}

o4 : Hyperplane Arrangement 

i5 : C = A ++ B

o5 = {w, x, w - x, y, z, y + z}

o5 : Hyperplane Arrangement 

i6 : gens ring C

o6 = {w, x, y, z}

o6 : List

i7 : assert (degrees ring C === {{1}, {1}, {1}, {1}})

i8 : 
