Deciding ML typability is complete for deterministic exponential time

@inproceedings{Mairson1989DecidingMT,
  title={Deciding ML typability is complete for deterministic exponential time},
  author={Harry G. Mairson},
  booktitle={POPL '90},
  year={1989}
}
A well known but incorrect piece of functional programming folklore is that ML expressions can be efficiently typed in polynomial time. In probing the truth of that folklore, various researchers, including Wand, Buneman, Kanellakis, and Mitchell, constructed simple counterexamples consisting of typable ML programs having length n, with principal types having &OHgr;(2cn) distinct type variables and length &OHgr;(22cn). When the types associated with these ML constructions were represented as… 

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