How to write: trace(P*P')

How can i write::

where P is 2*3 matrix
P’ is Hermitian of P
also, P is on of optimization variables


Depending on how that is used, you might be able to avoid the squaring, thereby improving numerical properties of the problem. For instance,
trace(P*P') <= c
can be formulated as
norm(P,'fro') <= sqrt(c)

Thank you so much.

I want to write constraint that:
trace(P*P’)>=0 ‘positive value’
but it is unacceptable in cvx ( convex>= constant) so how I can write it in cvx?

Thank you in advance

I thought


is nonnegative for all P so what is the point of this constraint?

Note the constraint

trace(P*P’) >= w

is nonconvex for all w>0.