English

No solvable lambda-value term left behind

Logic in Computer Science 2019-03-14 v3

Abstract

In the lambda calculus a term is solvable iff it is operationally relevant. Solvable terms are a superset of the terms that convert to a final result called normal form. Unsolvable terms are operationally irrelevant and can be equated without loss of consistency. There is a definition of solvability for the lambda-value calculus, called v-solvability, but it is not synonymous with operational relevance, some lambda-value normal forms are unsolvable, and unsolvables cannot be consistently equated. We provide a definition of solvability for the lambda-value calculus that does capture operational relevance and such that a consistent proof-theory can be constructed where unsolvables are equated attending to the number of arguments they take (their "order" in the jargon). The intuition is that in lambda-value the different sequentialisations of a computation can be distinguished operationally. We prove a version of the Genericity Lemma stating that unsolvable terms are generic and can be replaced by arbitrary terms of equal or greater order.

Keywords

Cite

@article{arxiv.1604.08383,
  title  = {No solvable lambda-value term left behind},
  author = {Á. García-Pérez and P. Nogueira},
  journal= {arXiv preprint arXiv:1604.08383},
  year   = {2019}
}

Comments

43 pages

R2 v1 2026-06-22T13:43:21.843Z