English
Two dfinsupps are disjoint iff their supports are disjoint.
Русский
Два dfinsupp попарно несоприкасаются тогда и только тогда, когда их поддержки не пересекаются.
LaTeX
$$$\mathrm{Disjoint}(f,g) \iff \mathrm{Disjoint}(f.\mathrm{support}, g.\mathrm{support})$$$
Lean4
nonrec theorem disjoint_iff : Disjoint f g ↔ Disjoint f.support g.support :=
by
rw [disjoint_iff, disjoint_iff, DFinsupp.bot_eq_zero, ← DFinsupp.support_eq_empty, DFinsupp.support_inf]
rfl