English
The support of the pointwise supremum equals the union of supports: (f ⊔ g).support = f.support ∪ g.support.
Русский
Опора точечного верхнего也 предельного равна объединению опор: supp(f ⊔ g) = supp(f) ∪ supp(g).
LaTeX
$$$ (f \\sup g).\\operatorname{support} = f.\\operatorname{support} \\cup g.\\operatorname{support} $$$
Lean4
@[simp]
theorem support_sup [DecidableEq ι] (f g : ι →₀ α) : (f ⊔ g).support = f.support ∪ g.support :=
by
ext
simp only [mem_support_iff, Ne, sup_apply, ← nonpos_iff_eq_zero, sup_le_iff, mem_union, not_and_or]