I have a simple infeasible problem as below. Maximize z = 4x1 + 3x2 2x1 - x2 >= 6 x1 + x2 <= 2 x1 and x2 >= 0 After solving I see that the termination status says 'ok' rather than saying 'infeasible'. May I know if something is wrong with the formulation in code? # Create a concrete model model = ConcreteModel() # Define variables with initialization and domain model.x1 = Var(domain=NonNegativeReals, initialize=0.0) model.x2 = Var(domain=NonNegativeReals, initialize=0.0) # Define the objective function model.obj = Objective(expr=4 * model.x1 + 3 * model.x2, sense=maximize) # Define the constraints model.constraint1 = Constraint(expr=2 * model.x1 - model.x2 >= 6) model.constraint2 = Constraint(expr=model.x1 + model.x2 <= 2) # Solve the model using the GLPK solver solver = SolverFactory('glpk') results = solver.solve(model)