Lecture 5: Algorithms for unfolding 2D chains, infinitesimally locked linkages, locked 3D chains (knitting needles), pocket flipping, Erdős-Nagy Theorem, deflations, flipturns
Page 2: Infinitesimally locked linkages, locked within ε, strongly locked, connections to rigidity, locked trees, infinitesimal carpenter's rule conjecture
You can view the paper by Alt, Knauer, Rote, and Whitesides proving PSPACE-hardness of deciding reachability between two configurations of a 2D tree or a 3D chain.
You can view the paper about infinitesimally locked linakges.
These are rough, personal lecture notes handwritten by Erik Demaine used during lecture. Their primary purpose is for reading/review by students of the class.