-- -*- M2-comint -*- hash: 10350953674802560663

i1 : n = 4;

i2 : isLowerSemimodular chain n

o2 = true

i3 : isLowerSemimodular booleanLattice n

o3 = true

i4 : P = poset {{1, 2}, {1, 5}, {2, 3}, {2, 4}, {3, 7}, {4, 7}, {5, 4}, {5, 6}, {6, 7}};

i5 : isLattice P

o5 = true

i6 : isLowerSemimodular P

o6 = false

i7 : 
