再生核研究所声明 744（2024.1.26) 大きな証明検証システム達が　ゼロ除算1/0=0

再生核研究所声明 744（2024.1.26) 大きな証明検証システム達が　ゼロ除算1/0=0/0=0　を保証している

これは　ニュースを解説調で述べたい：　先ずメール：

From:	Xena <comment-reply@wordpress.com>
返信先:	Xena <comment+ed083_jbv9l7glxtxu9n-40-k9f1jssyo367jw6a9xf67scrg@comment.wordpress.com>
To:	saburou.saitoh@gmail.com
日付:	2024/01/21 21:39
件名:	[Xena] xenaproject commented on Division by zero in type theory: a FAQ
送信元:	b.wordpress.com
署名元:	wordpress.com

で　次の事が知らされた：

Xena

New comment!

xenaproject just commented on Division by zero in type theory: a FAQ.

主要部は次のようである：

Division by zero in type theory: a FAQ

Posted on July 5, 2020 by xenaproject

Hey! I heard that Lean thinks 1/0 = 0. Is that true?

Yes. So do Coq and Isabelle and many other theorem provers.

Doesn’t that lead to contradictions?

No. It just means that Lean’s / symbol doesn’t mean mathematical division. Let denote the real numbers. Let’s define a function by if and .

Does making that definition give us a contradiction in mathematics? No, of course not! It’s just a definition. Lean uses the symbol / to mean . As does Coq, Isabelle etc. Lean calls it real.div by the way, not .

But doesn’t that lead to confusion?

It certainly seems to lead to confusion on Twitter. But it doesn’t lead to confusion when doing mathematics in a theorem prover. Mathematicians don’t divide by 0 and hence in practice they never notice the difference between real.div and mathematical division (for which 1/0 is undefined). Indeed, if a mathematician is asking what Lean thinks 1/0 is, one might ask the mathematician why they are even asking, because as we all know, dividing by 0 is not allowed in mathematics, and hence this cannot be relevant to their work. In fact knowing real.div is the same as knowing mathematical division; any theorem about one translates into a theorem about the other, so having real.div is equivalent to having mathematical division.

https://xenaproject.wordpress.com/2020/07/05/division-by-zero-in-type-theory-a-faq/
What is the Xena project?

My name’s Kevin Buzzard and I’m a professor of pure mathematics at Imperial College in London, specialising in arithmetic geometry and the Langlands program, a branch of modern algebraic number theory. I believe that digitising mathematics is important, for the simple reason that digitising anything enables you to do new things with it.

Currently the computer proof systems we have are not good enough to tell mathematical researchers anything new about the p-adic Langlands program or other trendy Fields Medally things, so the top mathematical researchers tend not to be interested in them. However I am not so crazy to believe that they will never be useful to us, and the point of the Xena project is to make it happen sooner.

サイトの責任者は次のようである：

英語から翻訳-ケビン・マーク・バザードは英国の数学者であり、現在はロンドンのインペリアル・カレッジで純粋数学の教授を務めています。彼は数論幾何学とラングランズプログラムを専門としています。 ウィキペディア（英語)

原文を見る

学歴： ケンブリッジ大学、 トリニティ・カレッジ

映画： Thinking Space

受賞歴： ホワイトヘッド賞 (2002年)、 ベリック賞 (2008年)

学術アドバイザー：リチャード・テイラー

Leanは　プログラミング言語および証明支援系(theorem prover)（英語版）である。

帰納型（英語版）を伴うCalculus of constructions（英語版）に基づく。

解説[編集]

LeanプロジェクトはGitHubでホストされているオープンソース（英語版）・プロジェクトである。2013年にMicrosoft ResearchのLeonardo de Mouraによって立ち上げられた^[1]。

https://ja.wikipedia.org/wiki/Lean_(%E8%A8%BC%E6%98%8E%E3%82%A2%E3%82%B7%E3%82%B9%E3%82%BF%E3%83%B3%E3%83%88)

The Coq Proof Assistant: Welcome!

Coqは、証明支援システムの一つ。Coqの核はプログラミング言語Gallina（英語版）を用いる。フランス国立情報学自動制御研究所のPI.R2チーム(PPS研究所内にある)が、エコール・ポリテクニーク、フランス国立工芸院、パリ第7大学、パリ第11大学と(かつてリヨン高等師範学校とも)共同して開発している。Hugo Herbelinが事実上の開発代表者である。

https://ja.wikipedia.org/wiki/Coq

The Isabelle^[a] automated theorem prover is a higher-order logic (HOL) theorem prover, written in Standard ML and Scala. As an LCF-style theorem prover, it is based on a small logical core (kernel) to increase the trustworthiness of proofs without requiring — yet supporting — explicit proof objects.Isabelle is available inside a flexible system framework allowing for logically safe extensions, which comprise both theories as well as implementations for code-generation, documentation, and specific support for a variety of formal methods. It can be seen as an IDE for formal methods. In recent years, a substantial number of theories and system extensions have been collected in the Isabelle Archive of Formal Proofs (Isabelle AFP)^[2]