Modeling a constraint in MILP CVX

Hi there,
I’m sorry to bother you with this simple question. I’m new to CVX and I would like to model a simple model of the minimum cover vertex set problem. I believe that the original problem is such as
Min sum (x)
s.t
x_u + x_v >= 1
x is a binary variable, where it is 1 if the vertex v is included in the minimum set and 0 otherwise.
I have added another binary variable z_ev
sum (z_ev ) >= k; k is a parameter
z_ev where it is 1 if vertex v is in the set and 0 otherwise, and e is the edge between node v and node u , node u is not member of the minimum set.
So, x is variable controlling the vertices and z controlling the edges.

I hope you can help me with modeling the second constraint.
I’m conduesd about the interaction between if nodes is decieded to be in the set (i.e., x_v = 1) and the edge connected to it.
P.S the edges is defined as e={u,v} where u,v are the vertices incident to that edge.

Thank you so much in advance.

This is a modeling question, not a CVX question. I suggest you post at https://or.stackexchange.com/ , saying you want a MILP model, and don’t even mention CVX.

I appreciate your reply. thank you for the advice.
I got the idea of posting this question here because I saw some related questions were answered by you.
Thanks again

Well, now we have https://or.stackexchange.com/ , so I am directing some questions to there.