Theorem: ENat.tsum_subtype_const (Matroid/ForMathlib/ENatTopology.lean)

State before:
α : Type u_1
β : Type u_2
ι : Type u_3
s✝ : Set α
n : ℕ∞
f g : α → ℕ∞
s : Set α
c : ℕ∞
⊢ ∑' (x : ↑s), c = c * s.encard
Tactic:
rw [← ENat.tsum_one s, ENat.mul_tsum, mul_one]
State after:
no goals