English
If l ∈ c is such that hl ∈ c, then (sSup c)(x) = l(x) for appropriate x in domain.
Русский
Если l ∈ c и hl соответствует l, то (sup c)(x) = l(x) на соответствующем x.
LaTeX
$$$$ (\\mathrm{sSup}(c))\\;\\text{toFun'}\\langle x, \\cdots \\rangle = l(x) $$$$
Lean4
protected theorem sSup_apply {c : Set (E →ₗ.[R] F)} (hc : DirectedOn (· ≤ ·) c) {l : E →ₗ.[R] F} (hl : l ∈ c)
(x : l.domain) : (LinearPMap.sSup c hc) ⟨x, (LinearPMap.le_sSup hc hl).1 x.2⟩ = l x :=
by
symm
apply (Classical.choose_spec (sSup_aux c hc) hl).2
rfl