Formally characterize the structure of a linked chain, and infer (a) that pulling on one end will cause the whole chain to follow; (b) that the chain is very flexible; (c) that cutting one link will give two shorter chains and that linking two chains together end to end gives a longer chain.
Contributed by Ernie Davis ( davise@cs.nyu.edu), New York University, U.S.A. (18th September 1997)