English
For two partial maps f and g, the domain of their supremum equals the join of their domains: dom(f.sup g h) = dom(f) ⊔ dom(g).
Русский
Область определения их верхнего предела равна объединению областей определения: dom(f.sup g h) = dom(f) ⊔ dom(g).
LaTeX
$$$\\mathrm{domain}(f\\;\\mathrm{sup}\\;g\\;h)=\\mathrm{domain}(f)\\sqcup\\mathrm{domain}(g)$$$
Lean4
theorem mkSpanSingleton_apply (K : Type*) {E F : Type*} [DivisionRing K] [AddCommGroup E] [Module K E] [AddCommGroup F]
[Module K F] {x : E} (hx : x ≠ 0) (y : F) :
mkSpanSingleton x y hx ⟨x, (Submodule.mem_span_singleton_self x : x ∈ Submodule.span K { x })⟩ = y :=
LinearPMap.mkSpanSingleton'_apply_self _ _ _ _