Theorem: LinearMap.extendSubtype_apply (Matroid/ForMathlib/LinearAlgebra/StdBasis.lean)

State before:
α : Type u_1
R✝¹ : Type u_2
η : Type u_3
ι : Type u_4
R✝ : Type u_5
inst✝¹ : Semiring R✝
s✝ : Set α
R : Type u_6
inst✝ : Semiring R
s : Set α
f : ↑s → R
y : ↑s
⊢ (extendSubtype R s) f ↑y = f y
Tactic:
rw [extendSubtype, Function.ExtendByZero.linearMap_apply, Subtype.coe_injective.extend_apply]
State after:
no goals