Linear Coding of Non-linear Hierarchies: Revitalization of an Ancient Classification Method

The article treats the problem of forcing entities into a linear order which could be more naturally organized in a non-linear hierarchy (e.g., books in a library, products in a warehouse or store,...). The key idea is to apply a technique for the linear coding of non-linear hierarchies which has been developed by the ancient grammarian Panini for the concise representation of sound classes. The article introduces briefly Panini's technique and discusses a general theorem stating under which condition his technique can be applied.