[…] the only attempt to evaluate a fairly full and complex subsystem of a grammar is in Chomsky (1951) [Chomsky, N. 1951. Morphophonemics of Modern Hebrew Unpublished Master’s thesis, University of Pennsylvania], but even here all that is shown is that the value of the system is a "local maximum" in the sense that interchange of adjacent rules decreases value.
- Chomsky (1969), Pag. 44