Documentation

Matroid.NonspanningCircuit

structure Matroid.IsNonspanningCircuit {α : Type u_1} (M : Matroid α) (C : Set α) :
Instances For
    theorem Matroid.IsNonspanningCircuit.subset_ground {α : Type u_1} {M : Matroid α} {C : Set α} (h : M.IsNonspanningCircuit C) :
    C ⊆ M.E
    theorem Matroid.isBase_iff_forall_not_isNonspanningCircuit_subset {α : Type u_1} {M : Matroid α} [M.RankFinite] {B : Set α} (hBE : B ⊆ M.E) :
    M.IsBase B ↔ B.encard = M.eRank ∧ ∀ C ⊆ B, ¬M.IsNonspanningCircuit C
    theorem Matroid.ext_isNonspanningCircuit {α : Type u_1} {M N : Matroid α} (hE : M.E = N.E) (hr : M.eRank = N.eRank) [M.RankFinite] (hMN : ∀ C ⊆ M.E, M.IsNonspanningCircuit C ↔ N.IsNonspanningCircuit C) :
    M = N

    Two matroids with the same finite rank, the same ground set, and the same nonspanning circuits are equal.

    theorem Matroid.ext_isCircuit_encard_le {α : Type u_1} {M N : Matroid α} (hE : M.E = N.E) (hr : M.eRank = N.eRank) [M.RankFinite] (hMN : ∀ C ⊆ M.E, C.encard ≤ M.eRank → (M.IsCircuit C ↔ N.IsCircuit C)) :
    M = N