I am trying to maximize the L-1/2 norm of a vector in MATLAB using CVX, but the function ‘norm’ naturally does not accept p = 1/2 since it is not really a norm. So, I tried to construct the expression myself and encountered the error

Disciplined convex programming error:

Illegal operation: {concave} .^ {2}

(Consider POW_P, POW_POS, or POW_ABS instead.)

And using the function ‘pow_p’ yields the error

Disciplined convex programming error:

Illegal operation: pow_p( {concave}, {2} )

I know that the expression ’ maximize ||x||_(1/2) ’ is convex, but I cannot use CVX for it. How can I overcome this? Thank you in advance.