Matroid.cRk_inter_add_cRk_union_le

∀ {α : Type u} (M : Matroid α) [M.InvariantCardinalRank] (X Y : Set α),
  M.cRk (X ∩ Y) + M.cRk (X ∪ Y) ≤ M.cRk X + M.cRk Y

The Cardinal rank function is submodular.

Defined in: Mathlib.Combinatorics.Matroid.Rank.Cardinal
Cited by: 0 results in Mathlib
Foundations: Depth 92 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes: Matroid.InvariantCardinalRank

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