(\star)=\left(\left(\sum_{k=1}^{n}{|x_k|^p}\right)^{\frac{1}{p}}+\left(\sum_{k=1}^{n}{|y_k|^p}\right)^{\frac{1}{p}}\right)\left(\sum_{k=1}^{n}|x_k+y_k|^{p}\right)^{\frac{1}{q}