{"title":"单型λ微积分中λβ约简的证明理论研究","authors":"William Stirton","doi":"10.1016/j.apal.2025.103657","DOIUrl":null,"url":null,"abstract":"<div><div>The paper defines a function <em>f</em> from simply typed <em>λ</em>-terms to natural numbers and proves that, if <span><math><msup><mrow><mi>M</mi></mrow><mrow><mo>⁎</mo></mrow></msup></math></span> is a simply typed <em>λ</em>-term formed by contracting an arbitrary <em>λβ</em>-redex within another term <em>M</em>, then <span><math><mi>f</mi><mo>(</mo><msup><mrow><mi>M</mi></mrow><mrow><mo>⁎</mo></mrow></msup><mo>)</mo><mo><</mo><mi>f</mi><mo>(</mo><mi>M</mi><mo>)</mo></math></span>. Unlike previous proofs of similar theorems, the redex contracted may be completely arbitrary, i.e. without any restriction on rule (<em>ξ</em>). The function <em>f</em> itself is related to, and no more computationally difficult than, a similar-looking function defined in Schütte's <em>Proof Theory</em> (1977).</div></div>","PeriodicalId":50762,"journal":{"name":"Annals of Pure and Applied Logic","volume":"177 1","pages":"Article 103657"},"PeriodicalIF":0.6000,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Proof-theoretic investigation of λβ-reduction in the simply typed λ-calculus\",\"authors\":\"William Stirton\",\"doi\":\"10.1016/j.apal.2025.103657\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>The paper defines a function <em>f</em> from simply typed <em>λ</em>-terms to natural numbers and proves that, if <span><math><msup><mrow><mi>M</mi></mrow><mrow><mo>⁎</mo></mrow></msup></math></span> is a simply typed <em>λ</em>-term formed by contracting an arbitrary <em>λβ</em>-redex within another term <em>M</em>, then <span><math><mi>f</mi><mo>(</mo><msup><mrow><mi>M</mi></mrow><mrow><mo>⁎</mo></mrow></msup><mo>)</mo><mo><</mo><mi>f</mi><mo>(</mo><mi>M</mi><mo>)</mo></math></span>. Unlike previous proofs of similar theorems, the redex contracted may be completely arbitrary, i.e. without any restriction on rule (<em>ξ</em>). The function <em>f</em> itself is related to, and no more computationally difficult than, a similar-looking function defined in Schütte's <em>Proof Theory</em> (1977).</div></div>\",\"PeriodicalId\":50762,\"journal\":{\"name\":\"Annals of Pure and Applied Logic\",\"volume\":\"177 1\",\"pages\":\"Article 103657\"},\"PeriodicalIF\":0.6000,\"publicationDate\":\"2025-09-23\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Annals of Pure and Applied Logic\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S016800722500106X\",\"RegionNum\":2,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"LOGIC\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Annals of Pure and Applied Logic","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S016800722500106X","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"LOGIC","Score":null,"Total":0}
Proof-theoretic investigation of λβ-reduction in the simply typed λ-calculus
The paper defines a function f from simply typed λ-terms to natural numbers and proves that, if is a simply typed λ-term formed by contracting an arbitrary λβ-redex within another term M, then . Unlike previous proofs of similar theorems, the redex contracted may be completely arbitrary, i.e. without any restriction on rule (ξ). The function f itself is related to, and no more computationally difficult than, a similar-looking function defined in Schütte's Proof Theory (1977).
期刊介绍:
The journal Annals of Pure and Applied Logic publishes high quality papers in all areas of mathematical logic as well as applications of logic in mathematics, in theoretical computer science and in other related disciplines. All submissions to the journal should be mathematically correct, well written (preferably in English)and contain relevant new results that are of significant interest to a substantial number of logicians. The journal also considers submissions that are somewhat too long to be published by other journals while being too short to form a separate memoir provided that they are of particular outstanding quality and broad interest. In addition, Annals of Pure and Applied Logic occasionally publishes special issues of selected papers from well-chosen conferences in pure and applied logic.