Converts a list or set of indices to the list of elements of the matroid with those indices. The inverse of this function is indicesOf.
i1 : M = matroid({a,b,c,d},{{a,b},{a,c}})
o1 = a matroid of rank 2 on 4 elements
o1 : Matroid
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i2 : M_2 o2 = c o2 : Symbol |
i3 : M_{0,2,3}
o3 = {a, c, d}
o3 : List
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i4 : B = (bases M)#0
o4 = set {0, 1}
o4 : Set
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i5 : M_B
o5 = {a, b}
o5 : List
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If used with the operator _*, then the list of all elements in M is returned. This is useful in conjunction with apply, to iterate over all elements in a matroid.
i6 : F7 = specificMatroid "fano" o6 = a matroid of rank 3 on 7 elements o6 : Matroid |
i7 : M4 = matroid completeGraph 4 o7 = a matroid of rank 3 on 6 elements o7 : Matroid |
i8 : all(F7_*, x -> #getIsos(F7 \ {x}, M4) > 0)
o8 = true
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There are important differences between this method and groundSet: see that page for more details.