English
The coercion from Finset to Set commutes with SDiff: the set of s \\ t equals the set difference of the sets.
Русский
Переход из Finset в Set сохраняет операцию SDiff: множество разности равно разности множеств.
LaTeX
$$$ \\uparrow (s \\setminus t) = (s \\setminus t)^{\\text{Set}}. $$$
Lean4
@[simp, grind =, norm_cast]
theorem coe_sdiff (s₁ s₂ : Finset α) : ↑(s₁ \ s₂) = (s₁ \ s₂ : Set α) :=
Set.ext fun _ => mem_sdiff