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isElementaryQuotient -- whether a matroid is an elementary quotient of another matroid



This function is provided by the package Matroids.

An elementary quotient of a matroid N is a quotient M whose rank is the rank of N minus one. Elementary quotients are completely determined by the modular cut of flats in M (which are also flats of N) whose rank in M is one less than their rank in N. Examples of elementary quotients of N are its principal truncations with respect to a given flat F.

i1 : N = matroid completeGraph 5

o1 = a "matroid" of rank 4 on 10 elements

o1 : Matroid
i2 : F = set {0,1,4};
i3 : TFN = truncate(F, N)

o3 = a "matroid" of rank 3 on 10 elements

o3 : Matroid
i4 : isElementaryQuotient(TFN, N)

o4 = true
i5 : T2N = truncate(2, N)

o5 = a "matroid" of rank 2 on 10 elements

o5 : Matroid
i6 : isElementaryQuotient(T2N, N)

o6 = false

See also

Ways to use isElementaryQuotient :

For the programmer

The object isElementaryQuotient is a method function.