Labeling, maximality and the head - Phrase distinction

Combining the labeling algorithm of Chomsky (2013) with bare phrase structure raises the question of how heads (simple or complex) and phrases can be distinguished. I propose a notational device which draws the distinction in a way which solves technical problems for the labeling algorithm. Focusing on phrasal movement, I show how the "halting problem" for wh-movement, and in particular the freezing effects arising in criterial positions, can be derived from labeling and a maximality principle, restricting movement to maximal elements with a given label. Looking then at head movement, I argue that it can be made consistent with the No Tampering condition, and work out the labeling algorithm for structures derived by head movement. Finally, I argue that the ban against excorporation in head movement can be analyzed as a case of freezing, and traced back, much as freezing in phrasal movement, to the maximality principle relativized to the head - phrase distinction.