English
Attaching mk to a multiset corresponds to mk of the attached multiset with a transformed card.
Русский
Прикрепление mk к мультисет приводит к mk прикрепленного мультисета с преобразованной картой.
LaTeX
$$$\\mathrm{attach}(\\mathrm{mk} \\, m \\; hc) = \\mathrm{mk} \\, m\\.\\mathrm{attach} \\, (\\mathrm{card\\_attach}(m) \\; \\mathrm{trans} \\; hc).$$$
Lean4
@[simp]
theorem attach_mk {m : Multiset α} {hc : Multiset.card m = n} :
attach (mk m hc) = mk m.attach (Multiset.card_attach.trans hc) :=
rfl