"Sthana" refers to "artha" ('meaning'), thus "nirvachanas" are merely place-holders in semantic space; one gets a different thought if one gets a different sentence to represent the same truth.By using "Ādeśa" rather than "vikāra", and holding on to "varna-samāmnāya" sound system, Pāṇini was able to achieve economy and brevity in the statements of algebraic system.