### 抜粋

Uniqueness for higher type term constructors in lambda calculi (e.g. surjective pairing for product types, or uniqueness of iterators on the natural numbers) is easily expressed using universally quantified conditional equations. We use a technique of Lambek [18] involving Mal'cev operators to equationally express uniqueness of iteration (more generally, higher-order primitive recursion) in a simply typed lambda calculus, essentially Godel's T [29,13]. We prove the following facts about typed lambda calculus with uniqueness for primitive recursors: (i) It is undecidable, (ii) Church-Rosser fails, although ground Church-Rosser holds, (iii) strong normalization (termination) is still valid. This entails the undecidability of the coherence problem for cartesian closed categories with strong natural numbers objects, as well as providing a natural example of the following computational paradigm: a non-CR, ground CR, undecidable, terminating rewriting system.

元の言語 | English |
---|---|

ページ（範囲） | 47-64 |

ページ数 | 18 |

ジャーナル | Theory and Applications of Categories |

巻 | 6 |

出版物ステータス | Published - 2000 12 1 |

外部発表 | Yes |

### ASJC Scopus subject areas

- Mathematics (miscellaneous)

## フィンガープリント A note on rewriting theory for uniqueness of iteration' の研究トピックを掘り下げます。これらはともに一意のフィンガープリントを構成します。

## これを引用

*Theory and Applications of Categories*,

*6*, 47-64.