-- -*- M2-comint -*- {* hash: -344371720 *}

i1 : A = typeA(3)

o1 = {x  - x , x  - x , x  - x , x  - x , x  - x , x  - x }
       1    2   1    3   1    4   2    3   2    4   3    4

o1 : Hyperplane Arrangement 

i2 : euler A -- for a real arrangement, equals number of bounded chambers

o2 = 2

i3 :