-- -*- M2-comint -*- {* hash: 431048826 *}

i1 : keys arrangementLibrary

o1 = {prism, (9_3)_2, notTame, Ziegler1, Hessian, nonFano, Ziegler2, X2,
     ------------------------------------------------------------------------
     MacLane, X3, braid, Pappus}

o1 : List

i2 : R = QQ[x,y,z];

i3 : A = arrangement("Pappus",R)

o3 = {x, y, z, x - y, y - z, x - y - z, 2x + y + z, 2x + y - z, 2x - 5y + z}

o3 : Hyperplane Arrangement 

i4 : poincare A

                 2      3
o4 = 1 + 9T + 27T  + 19T

o4 : ZZ[T]

i5 : isDecomposable A

o5 = false

i6 : A = arrangement("prism", ZZ/101) -- can also specify coefficient ring

o6 = {x , x , x , x , x  + x  + x , x  + x  + x }
       1   2   3   4   1    2    4   1    3    4

o6 : Hyperplane Arrangement 

i7 : ring A

      ZZ
o7 = ---[x , x , x , x ]
     101  1   2   3   4

o7 : PolynomialRing

i8 :