Question:

first question

a,b,c,d are four different numbers,I don’t know how to express it in a constraint.

second question:

Q is variable,h and g are row vectors,My expression is`h*Q*h/(1+g*Q*g)`

,The error shows “Disciplined convex programming error:

Cannot perform the operation: {real affine} ./ {real affine}“

I need your help. If it is convenient for you, please help me. I am looking forward to your reply.