Easy Terms in the Lambda Calculus
Giuseppe Jacopini, Marisa Venturini Zilli · Fundamenta Informaticae · 1985
This paper, a revised version of the one [4] presented at the Logic Colloquium ’82, concerns closed unsolvable λ-terms, named easy, which are terms such that they can be consistently equated to arbitrary closed ones. Some general results are obtained, mainly sufficient or necessary conditions for proving that an unsolvable λ-term is easy.