Cannot perform the operation norm( {concave}, 2 )

[Yanc14 (yang-cong)]

[Mark_L_Stone]

You can algebraically reformulate
(sqrt(x)/eta - 1)^2
to
x/eta^2 - 2*sqrt(x)/eta + 1
and then you can apply sum(...) to that.

[Yanc14 (yang-cong)]

thank u for your help!