`square_pos(norm(...))`

or

`pow_pos(norm(...),2)`

As can be seem below, when the 2nd argument of `pow_p`

is 2, the first argument of `pow_p`

must be affine, which `norm`

is not.

help pow_p

pow_p Positive branch of the power function.

pow_p(X,P) computes a convex or concave branch of the power function:

P < 0: pow_p(X,P) = X.^P if X > 0, +Inf otherwise

0 <= P < 1: pow_p(X,P) = X.^P if X >= 0, -Inf otherwise

1 <= P : pow_p(X,P) = X.^P if X >= 0, +Inf otherwise

Both P and X must be real.

```
Disciplined convex programming information:
The geometry of pow_p(X,P) depends on the precise value of P,
which must be a real constant:
P < 0: convex and nonincreasing; X must be concave.
0 <= P < 1: concave and nondecreasing; X must be concave.
1 <= P : convex and nonmonotonic; X must be affine.
In all cases, X must be real.
```