How to set a constraint that the variable's first column is the minimum value in the remaining columns

Now I have a problem.There is a constraint that the variable’s first column is the minimum value in the remaining columns.

For example, I want to have a matrix X like this:
[1,2,3;
4,5,6;
7,8,9]

I try to set X's constraint as:
    (-1)*x(:,1)<=0;
    %        -x1<=0
    repmat(x(:,1),1,3)-y(:,2:3)<=0;  
    %        x1-x23<=0

But actually the X’s first column become zero.
The result as:
[0,2,3;
0,5,6;
0,8,9;]

This post was edited from the original to state have <= the minimum value rather than have the minimum value.

I don’t understand your question. Do you want
X(:,1) <= min(X(:,2:end),[],2).
For each row, that constrains the first element to have <= the minimum value in that row (but ties are allowed).

Yes I just mean this. Thank you very much

I try your code but the problem is still here.
X(:,1) <= min(X(:,2:end),[],2)

Although the first column is smaller than the last columns, it becomes zero not the minimum value.

I try to set constraint as:
X(:,1) = min(X(:,2:end),[],2)
I wish that the variable’s first column is the minimum value in the remaining columns.

But there is error as:
The following cvx variable(s) have been cleared or overwritten:
y
This is often an indication that an equality constraint was
written with one equals ‘=’ instead of two ‘==’. The model
must be rewritten before cvx can proceed.

Whoops, my constraint constrained the first column to be <= the minimum of the other columns. (I wrote it incorrectly, but have now fixed it).

To do what you want, you can’t use a constraint (==), because that is a non-convex equality constraint. You can’t do assignment (’=’) to a variable; that is why you got the error message. So what you do is declare X to have one fewer columns, and use a new variable X_min_per_row to be the minimum of the columns of the now reduced dimension X. Assume your original X was m by n.

variable X(m,n-1) 
expression X_min_per_row(m,1)
X_min_per_row = min(X,[],2);

Make adjustments in the rest of your program as needed in light of this. if you want to create the original X, you can do so by concatenation. X_original = [X_min_per_row X];

Because the expression X_min_per_row is not a scalar, it needs to be declared as an expression holder (array), as I have done, although expression X_min_per_row(m) could be used instead.

Thank you for your help.
When I add X_min_per_row to object function,it warns me that Illegal operation: {concave} + {convex}.
My Partial objective function is to minimize X_min_per_row
Maybe there is a good way to Convert {concave} into {convex}?

min is concave. So to do what you want requires introduction of binary variables to “linearize” the non-convex use of min. Look at the last bullet of https://www.fico.com/fico-xpress-optimization/docs/latest/mipform/dhtml/chap2s1.html?scroll=ssecminval to see how. I leave you to work out the details for your program.

Also, please read
Why isn't CVX accepting my model? READ THIS FIRST!

Thank you for your reply.
I will read these carefully.