-- -*- M2-comint -*- {* hash: 217202285 *}

i1 : R = QQ[x,y];

i2 : FA = EPY arrangement {x,y,x-y}

o2 = cokernel | -X_1 X_1+X_2+X_3 X_1     |
              | X_2  0           X_1+X_3 |

                                                        2
o2 : QQ[X , X , X ]-module, quotient of (QQ[X , X , X ])
         1   2   3                           1   2   3

i3 : betti res FA

            0 1 2
o3 = total: 2 3 1
         0: 2 3 1

o3 : BettiTally

i4 : A = typeA(4)

o4 = {x  - x , x  - x , x  - x , x  - x , x  - x , x  - x , x  - x , x  - x , x  - x , x  - x }
       1    2   1    3   1    4   1    5   2    3   2    4   2    5   3    4   3    5   4    5

o4 : Hyperplane Arrangement 

i5 : factor poincare A

o5 = (1 + T)(1 + 2T)(1 + 3T)(1 + 4T)

o5 : Expression of class Product

i6 : betti res EPY A

             0  1  2  3 4
o6 = total: 24 50 35 10 1
         0: 24 50 35 10 1

o6 : BettiTally

i7 :