Definition:  qualifies n vectors ${U}_{1}\text{,}\text{\hspace{0.17em}}{U}_{2}\text{,}\text{\hspace{0.17em}}\mathrm{...}\text{,}\text{\hspace{0.17em}}{U}_{n}$ where a linear combination such as ${\alpha}_{1}{U}_{1}+{\alpha}_{2}{U}_{2}+\mathrm{...}+{\alpha}_{n}{U}_{n}$ cannot be equal to zero unless all scalar coefficients ${\alpha}_{1}\text{,}\text{\hspace{0.17em}}{\alpha}_{2}\text{,}\text{\hspace{0.17em}}\mathrm{...}\text{,}\text{\hspace{0.17em}}{\alpha}_{n}$ are equal to zero
