-- -*- M2-comint -*- hash: 12518734516559988602

i1 : n = 4;

i2 : isUpperSemimodular chain n

o2 = true

i3 : isUpperSemimodular booleanLattice n

o3 = true

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

i5 : isLattice P

o5 = true

i6 : isUpperSemimodular P

o6 = false

i7 : 
