L1normi
L1normi, commonly called the L1 norm, is a norm on R^n defined for a vector x = (x1, ..., xn) by ||x||1 = sum_i |xi|. It satisfies positivity, homogeneity, and the triangle inequality, and it provides a measure of the magnitude of a vector based on the sum of the magnitudes of its components.
The L1 norm induces a distance (a metric) between two vectors x and y given by d1(x,
In optimization and statistics, the L1 norm is valued for promoting sparsity when used as a regularization
Examples: for x = (3, −4, 0), ||x||1 = 7. The distance between a and b, say (1, 2)