In my model, I am tracking the production date of certain products. It is possible to produce a product at time t, while allocating it to demand on time t+3. However, there is a maximum ‘age’ of a product. For example ‘If a product is older that three days, it cannot be allocated’.

Now, given an allocation variable v_Allocate(i_Order, i_AllocationDay, i_Product, i_ProductionDay), indicating the allocation on day i_AllocationDay to order i_Order of i_Product which has production day i_Production day, I would like to restrict the index range to ‘valid’ combinations e.g. production day >= t-3. 

If I would restrict the index domain on the variable like so:

index domain: (i_Order, i_AllocationDay, i_Product, i_ProductionDay) | i_ProductionDay >= i_AllocationDay - 3

Do I still need to add a separate constraint to ensure this production day restriction?

In addition: does it make sense to do this in the index domain?