matrix 2-norm and associated matrix condition number

Dear experts,

AFAIK maxima currently has no matrix 2-norm and no matrix condition number based on
2-norm.
In teaching the 2-norm/2-condition sometimes matters.

So I wrote simple beginners implementations of both concepts:

load("linearalgebra");

mat_norm2(A) := sqrt(last(sort(eigenvalues(transpose(A).A)[1])));
mat_norm2(matrix([3,-1],[-1,3]));  --> 4


mat_cond2(A) := mat_norm2(invert(A))*mat_norm2(A)$
mat_cond2(matrix([3,-1],[-1,3]));  --> 2

It works for me (and for some little tests), but I wonder if someone has written 
'alternative' Maxima functions using other or better math or maxima concepts.
Any hints are very welcome.

-- 
HTH  Wolfgang