A vector norm defined for a vector x = [x_1 x_2 ⋮ x_n], with complex entries by left bracketing bar x right bracketing bar _1 = sum_(r = 1)^n left bracketing bar x_r right bracketing bar . The L^1-norm left bracketing bar x right bracketing bar _1 of a vector x is implemented in the Wolfram Language as Norm[x, 1].