Let consider $L$ be a Leibniz algebra which is left nilpotent. ( I do not know what is left nilpotent of class 3).
A Leibniz algebra L is said to be nilpotent, if for lower central series there exists n ∈ N such that $L^{n} = 0$. The minimal number $n$ with this property is said to be index of nilpotency of algebra $L$. Is the class of nilpotency the same with index of nilpotency?
An n-dimensional Leibniz algebra is called null filiform if $dim L^{i}=n+1-i$, where $1 \leq i \leq n+1$. Is a left nilpotent Leibniz algebra of class 3 a null filiform Leibniz algebras?