Correcting a widespread error in unification algorithms

@article{Norvig1991CorrectingAW,
  title={Correcting a widespread error in unification algorithms},
  author={Peter Norvig},
  journal={Software: Practice and Experience},
  year={1991},
  volume={21}
}
  • Peter Norvig
  • Published 1 February 1991
  • Computer Science
  • Software: Practice and Experience
The unification of two patterns both containing variables is a ubiquitous operation in logic programming and in many artificial intelligence applications. Thus, many texts present unification algorithms. Unfortunately, at least seven of these presentations are incorrect. The common error occurs when logic variables are represented as binding lists; implementations that destructively update variable cells do not manifest the error. This note gives the examples that uncover the error and presents… Expand
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