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[Merged by Bors] - chore: reduce open Fin.NatCast #29443

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[Merged by Bors] - chore: reduce open Fin.NatCast #29443

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3 changes: 1 addition & 2 deletions Mathlib/LinearAlgebra/Matrix/GeneralLinearGroup/Card.lean
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Expand Up @@ -30,7 +30,6 @@ local notation "n" => Module.finrank K V

attribute [local instance] Fintype.ofFinite in
open Fintype in
open Fin.NatCast in -- TODO: should this be refactored to avoid needing the coercion?
/-- The cardinal of the set of linearly independent vectors over a finite dimensional vector space
over a finite field. -/
theorem card_linearIndependent {k : ℕ} (hk : k ≤ n) :
Expand All @@ -49,7 +48,7 @@ theorem card_linearIndependent {k : ℕ} (hk : k ≤ n) :
simp only [SetLike.coe_sort_coe, finrank_span_eq_card s.2, card_fin]
rw [Module.card_eq_pow_finrank (K := K)]
simp [card_congr (equiv_linearIndependent k), sum_congr _ _ this, ih (Nat.le_of_succ_le hk),
mul_comm, Fin.prod_univ_succAbove _ k]
mul_comm, Fin.prod_univ_succAbove _ (Fin.last k)]

end LinearIndependent

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