English
The dense range of Subtype.val is equivalent to density of the underlying set {x | p x}.
Русский
Плотность образа Subtype.val эквивалентна плотности множества {x | p x}.
LaTeX
$$$@[simp]\\; \\text{theorem } \\text{denseRange_subtype_val} : DenseRange (\\mathrm{Subtype}.val) \\leftrightarrow Dense\\{x \\mid p x\\}$$$
Lean4
theorem denseRange_id : DenseRange (id : X → X) :=
Function.Surjective.denseRange Function.surjective_id