Infeasible solutions in linear programming Is it possible to determine the cause of an infeasible linear programming model? If so, what's the approach?

Not really. Some solvers have tools called IIS (Irriducable Infeasible Sets) or Conflict Refiner. These tools can help but will not always point you to the real cause. Sometimes it can also help to formulate an Elastic Formulation: add slacks to the equations and add a penalty or cost to the objective. E.g. if you have a capacity constraint, allow always to rent (expensive) extra capacity.
