English
If G is nilpotent, then any quotient G/H by a normal subgroup H is also nilpotent.
Русский
Если G нильпотентна, то всякая фактор-группа G/H по нормальной подгруппе H тоже нильпотентна.
LaTeX
$$$\\operatorname{IsNilpotent}(G) \\;\\Rightarrow\\; \\operatorname{IsNilpotent}(G/H) \\quad (H \\trianglelefteq G)$$$
Lean4
/-- A quotient of a nilpotent group is nilpotent -/
instance nilpotent_quotient_of_nilpotent (H : Subgroup G) [H.Normal] [_h : IsNilpotent G] : IsNilpotent (G ⧸ H) :=
nilpotent_of_surjective (QuotientGroup.mk' H) QuotientGroup.mk_surjective