Theorem: UniformSpace.thickening_singleton (RMT4/uniform.lean)

State before:
ι : Type u_1
α : Type u_2
β : Type u_3
a : α
s t : Set α
x u v : Set (α × α)
⊢ thickening u {a} = ball a u
Tactic:
simp only [thickening, mem_singleton_iff, iUnion_iUnion_eq_left]
State after:
no goals