September 2014
Intermediate to advanced
336 pages
7h 53m
Japanese
Content preview from アンダースタンディング コンピュテーション ―単純な機械から不可能なプログラムまで
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7.9
ウルフラムの
2,3
チューリングマシン
251
チューリングマシンのシミュレーションを実行することができます。これは万能な計算を実現するのに
効率の良い方法とは言えませんが、このような単純なセルオートマトンが万能であるということは、や
はり技術的に大変興味深い現象です。
7.9
ウルフラムの
2,3
チューリングマシン
単純な万能システムを駆け足で紹介してきましたが、締めくくりとして、ルール110よりもさらに単
純なシステム、ウルフラムの2,3チューリングマシン（Wolfram's 2,3 Turing machine）を紹介しておき
ましょう。その名前は2つの状態と3つの文字（
a
、
b
、空白）に由来しており、6 つの規則しかありませ
ん。
図7-8
通常、このチューリングマシンには受理状態がないので停止しませんが、これは技術的詳細
だと言ってよいでしょう。生成の振る舞い（たとえば、テープ上への特定の文字パターンの
登場）を監視し、現在のテープが役に立つ出力を含んでいるか調べることによって、停止しな
い機械から結果を得ることができます。
ウルフラムの2,3チューリングマシンは、万能な計算をサポートするだけの能力を備えているように
は見えません。2007年にウルフラム・リサーチ社は、これが万能であることを証明した人に$25,000の
賞金を授与すると発表しました。その年の後半、アレックス・スミス（Alex Smith）が証明に成功し、
賞金を獲得しました（http://www.theguardian.com/technology/2 ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.