The norm of a Banach space $X$ is said to be uniformly rotund in every direction if $$\lim_{n→∞}||x_n−y_n||=0$$ whenever $$x_n,y_n∈SX$$ are such that $$\lim_{n→∞}||x_n+y_n||=2$$ and there is a $z∈X$ and real numbers $λ_n$ such that $$x_n−y_n=λ_nz$$ for all $n∈N$, then we have $$\lim_{n→∞}λ_n=0$$ I want know relation between of uniformly rotund in every direction and uniformly rotund and locally uniformly rotund

The norm of a Banach space $X$ is said to be uniformly rotund in every direction if $$\lim_{n→∞}\|x_n−y_n\|=0$$ whenever $$x_n,y_n∈SX$$ are such that $$\lim_{n→∞}\|x_n+y_n\|=2$$ and there is a $z∈X$ and real numbers $λ_n$ such that $$x_n−y_n=λ_nz$$ for all $n∈N$, then we have $$\lim_{n→∞}λ_n=0$$ I want know relation between of uniformly rotund in every direction and uniformly rotund and locally uniformly rotund