English
For a Unique index type ι, the two representations AddEquiv.finsuppUnique and Equiv.finsuppUnique coincide on v.
Русский
При уникальном индексе ι две представления AddEquiv.finsuppUnique и Equiv.finsuppUnique совпадают на v.
LaTeX
$$$AddEquiv.finsuppUnique \\; v = Equiv.finsuppUnique \\; v$$$
Lean4
theorem support_single_add {a : ι} {b : M} {f : ι →₀ M} (ha : a ∉ f.support) (hb : b ≠ 0) :
support (single a b + f) = cons a f.support ha := by
classical
have H := support_single_ne_zero a hb
rw [support_add_eq, H, cons_eq_insert, insert_eq]
rwa [H, disjoint_singleton_left]