English
If the image of a family under a linear map is linearly independent, then the original family is linearly independent.
Русский
Если образ семейства вектора под линейным отображением линейно независим, то исходное семейство также линейно независимо.
LaTeX
$$$\\\\mathrm{LinearIndependent}_R (f \\\\circ v) \\\\Rightarrow \\\\mathrm{LinearIndependent}_R v.$$$
Lean4
/-- If the image of a family of vectors under a linear map is linearly independent, then so is
the original family. -/
theorem of_comp (f : M →ₗ[R] M') (hfv : LinearIndependent R (f ∘ v)) : LinearIndependent R v :=
by
rw [LinearIndependent, Finsupp.linearCombination_linear_comp, LinearMap.coe_comp] at hfv
exact hfv.of_comp