How to hold a constant variable value consecutively?

I have been trying to model a constraint for a variable in an MIP formulation. My problem is like this; X(t) is a variable, whose value has to remain constant for some pre-defined consecutive periods after its value decreases. So, say at t=2, the X(t=2) value decreases from X(t=1), then X(t) should remain equal to X(t=2) for T consecutive periods following that decrease. Can anyone suggest me how can I do that in an MIP formulation?

Hello,

I can’t be of much help to you on this one, as I myself am looking for a solution to this problem.