English
There is a unique subalgebra of R over itself, i.e., Subalgebra R R has a single instance.
Русский
Существует единственный подалгебра над собой: Subalgebra R R имеет единственный экзепляр.
LaTeX
$$$ \\text{Subalgebra.instUnique} : \\mathrm{Unique} (\\mathrm{Subalgebra} \\ R \\ R) $$$
Lean4
instance : Unique (Subalgebra R R) :=
{ inferInstanceAs (Inhabited (Subalgebra R R)) with
uniq := by
intro S
refine le_antisymm ?_ bot_le
intro _ _
simp only [Set.mem_range, mem_bot, algebraMap_self_apply, exists_apply_eq_apply, default] }