-- -*- M2-comint -*- hash: 1731184635859429192

i1 : M = matroid({a,b,c,d},{{a,b},{a,c}})

o1 = a "matroid" of rank 2 on 4 elements

o1 : Matroid

i2 : latticeOfFlats M

o2 = Relation Matrix: | 1 1 1 1 |
                      | 0 1 0 1 |
                      | 0 0 1 1 |
                      | 0 0 0 1 |

o2 : Poset

i3 : 
