An ordered list $\{B_1, \ldots, B_k\}$ of sets is a basis of a flag matroid $\mathbf M = \{M_1, \ldots, M_k\}$ if $B_i$ is a basis of $M_i$ and $B_i \subseteq B_{i+1}$ for all $i$. This method computes the bases of a flag matroid.
i1 : FM = flagMatroid {uniformMatroid(2,4),uniformMatroid(3,4)}
o1 = a flag matroid with rank sequence {2, 3} on 4 elements
o1 : FlagMatroid
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i2 : bases FM
o2 = {{set {0, 1}, set {0, 1, 2}}, {set {0, 1}, set {0, 1, 3}}, {set {0, 2},
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set {0, 2, 3}}, {set {0, 2}, set {0, 1, 2}}, {set {1, 2}, set {1, 2,
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3}}, {set {1, 2}, set {0, 1, 2}}, {set {0, 3}, set {0, 2, 3}}, {set {0,
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3}, set {0, 1, 3}}, {set {1, 3}, set {1, 2, 3}}, {set {1, 3}, set {0, 1,
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3}}, {set {2, 3}, set {0, 2, 3}}, {set {2, 3}, set {1, 2, 3}}}
o2 : List
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