Matrix column norm : colnorm colNorm

colnorm (or colNorm) takes as argument a matrix A = a_{j, k}.
colnorm (or colNorm) returns $\max_{j}^{}$($\sum_{k}^{}$(| a_{j, k}|)).
Input :

colnorm([[1,2],[3,-4]])

or

colNorm([[1,2],[3,-4]])

Output :

6

Indeed : max(1 + 3, 2 + 4) = 6