I would like to pose you a terminological question, regarding the following quotes from Noam Chomsky's work:
"A strong feature must be eliminated (almost) immediately upon its introduction into the phrase marker; otherwise, the derivation cancels."
"A strong feature that is not checked (and eliminated) in overt syntax causes a derivation to crash at LF." [LF= Logical Form]
" ‘‘strong’’ features are visible at PF and ‘‘weak’’ features invisible at PF. These features are not legitimate objects at PF; they are not proper components of phonetic matrices. Therefore, if a strong feature remains after Spell-Out, the derivation crashes."
"Alternatively, weak features are deleted in the PF component so that PF rules can apply to the phonological matrix that remains; strong features are not deleted so that PF rules do not apply, causing the derivation to crash at PF." [PF = Phonetic Form]
"The language L determines a set of derivations (computations). A derivation converges at one of the interface levels [PF, LF] if it yields a representation satisfying FI [FI = Full Interpretation] at this level, and converges if it converges at both interface levels, PF and LF; otherwise, it crashes. "
Chomsky is taking some kind of computer-science terminology, but I am not sure whether he makes some systematic and standard use of the terms or whether he just loosely hovers around them. The idea of a computation crashing (or being blocked with no chance of going forward, or of the system collapsing, whatever) seems quite intuitive, but, does it refer to a technical use from his part? I am more interested, though, in the rationale behind "convergence". Does it mean the derivation converges to a numerical value $0$?
Thanks in advance for your replies.