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 |

i2 : M_2 o2 = c o2 : Symbol |

i3 : M_{0,2,3} o3 = {a, c, d} o3 : List |

i4 : B = (bases M)#0 o4 = set {0, 1} o4 : Set |

i5 : M_B o5 = {a, b} o5 : List |

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 |

There are important differences between this method and groundSet: see that page for more details.