English
For l : (Σ i, αs i) →₀ M and i ∈ ι, i is in splitSupport(l) if and only if split l i ≠ 0.
Русский
Для l : (Σ i, αs i) →₀ M и i ∈ ι, i принадлежит splitSupport(l) тогда и только тогда, когда split l i ≠ 0.
LaTeX
$$$i \\in \\mathrm{splitSupport}(l) \\iff \\mathrm{split}(l,i) \\neq 0$$$
Lean4
theorem mem_splitSupport_iff_nonzero (i : ι) : i ∈ splitSupport l ↔ split l i ≠ 0 :=
by
classical
rw [splitSupport, mem_image, Ne, ← support_eq_empty, ← Ne, ← Finset.nonempty_iff_ne_empty, split, comapDomain,
Finset.Nonempty]
simp only [Finset.mem_preimage, exists_and_right, exists_eq_right, mem_support_iff, Sigma.exists, Ne]