I have a linear programming problem
min $c^T x$
$Ax\leq b$
However, in my problem, $A$ contains also some variables $y$, e.g.
$$A = \begin{pmatrix} y_1 & 4 \\ 3 & y_2 \end{pmatrix}$$
The question is that I want to find evaluationa value of $y$ such that the solution $x$ of the LP, for that fixed choice of $y$, is positive.
This question is different than normal formulation of parametric LP which typically only involves parameters in the cost vector or right-hand side of the constraints, and I do not want to simply use nonlinear programing. Any good solution?