-- -*- M2-comint -*- hash: 4848868891736187444

i1 : A = matrix{{0,0,0,1},{0,1,0,0},{1,-1,1,0},{0,1,0,0}}

o1 = | 0 0  0 1 |
     | 0 1  0 0 |
     | 1 -1 1 0 |
     | 0 1  0 0 |

              4       4
o1 : Matrix ZZ  <-- ZZ

i2 : isSchubertCM A

o2 = true

i3 : w = {1,3,2}

o3 = {1, 3, 2}

o3 : List

i4 : isSchubertCM w
We know from a theorem of Fulton that the quotient by any Schubert determinantal ideal is actually Cohen--Macaulay!

o4 = true

i5 : 
