If so, how? Can you? If not, why are you writing this program? That's a great quote. Do you have it in its original context? By dbueno at Thu, login or register to post comments. Google is your friend It's from this thread. By Daniel Yokomizo at Thu, login or register to post comments. Google doesn't ignore last names In fact, I did google for it, in several combinations; but all of those had his last name, I guess, so it only found references to this LtU thread.
By naasking at Wed, login or register to post comments. Yes Basically, fold captures the principle of one-step structural induction. By neelk at Thu, login or register to post comments. Ah thank you, The point about making life easier actually makes a lot of sense. By jdgallag at Wed, login or register to post comments.
You would probably be You would probably be interested in this thread on total functional programming. Yes That paper is exactly the kind of thing I was hoping to see. A very interesting read. By jdgallag at Thu, login or register to post comments. More transformations in terms of folds neelk wrote Basically, fold captures the principle of one-step structural induction.
For example, here are two examples which are doable but ugly with folds: Well, these particular examples are actually quite easily doable with folds. Not that annoying: How to zip folds: A library of fold transformers streams Once we know how to get takeWhile and dropWhile via folds, the rest is quite trivial.
By Oleg at Thu, login or register to post comments. By Sean McDirmid at Sat, login or register to post comments. Isn't Turing Completeness just derived from adding If not, what am I missing? By Burton Samograd at Mon, login or register to post comments. By Scott Johnson at Mon, login or register to post comments. Active forum topics Do names and symbols really imply semantics?
If so what to do about it? The Book of Shen 4th edition is now available online. Egel 0. Bespoke: live graphical language for granular synthesis. Recent comments Yup, this must hold for everything in the whole universe 14 hours 26 min ago On humans' complexity 15 hours 58 min ago re currying and parameter objects 1 week 2 days ago Pointfree modified with some operator precedence 1 week 3 days ago Is It an Advantage?
Home » forums » LtU Forum On the importance of Turing completeness In taking a graduate class in theoretical computer science, I developed a question that was never answered in a way that I felt comfortable with accepting, and now I can't stop thinking about it. By jdgallag at LtU Forum previous forum topic next forum topic other blogs reads Comment viewing options Flat list - collapsed Flat list - expanded Threaded list - collapsed Threaded list - expanded Date - newest first Date - oldest first 10 comments per page 30 comments per page 50 comments per page 70 comments per page 90 comments per page comments per page comments per page Select your preferred way to display the comments and click "Save settings" to activate your changes.
By neelk at Wed, login or register to post comments So a complete theorem So a complete theorem prover for FOL has to be written in a Turing-complete language. By neelk at Wed, login or register to post comments Hmmm Well I guess you have a point. By Matt M at Wed, login or register to post comments Writing an interpreter One can write an interpeter for an Turing-complete language in a Turing-complete language.
By Scott Johnson at Wed, login or register to post comments That said By Scott Johnson at Wed, login or register to post comments Ackerman Termination Charity was an interesting exercise in non-Turing complete programming languages that is capable of expressing the Ackerman function. By Tim Sweeney at Wed, login or register to post comments Also why Turing incompleteness. By Brandon Moore at Wed, login or register to post comments random algorithms, iterate-until-done algorithms Here's a couple more examples of algorithms that would be annoying to write in a language where all computations provably terminate.
By Carl Witty at Wed, login or register to post comments "Natural" programming languages are Turing-complete At least imperative ones. By Scott Johnson at Wed, login or register to post comments Right.
By Ehud Lamm at Wed, login or register to post comments well, not quite By Carl Witty at Wed, login or register to post comments C pointers can be arbitrarily large There is a requirement that they be convertible to type "long int" and back, but you can create a C dialect with bit pointers, if you like--sufficient to uniquely address any atom in the universe, and then some.
By Scott Johnson at Wed, login or register to post comments On a practical level On a practical level, it's much easier for those of us that are at the subgenius level to actually get our work done. By Chris Rathman at Wed, login or register to post comments Another point with SQL Would all those query optimizers--a key feature of RDBMS's that make SQL practical to use it's easy to write queries that, if implemented naively, would take a jakillion years to complete on even the fastest server --still be possible if SQL didn't limit itself to a logical foundation predicate calculus that wasn't Turing-complete?
By Scott Johnson at Wed, login or register to post comments Fighting the optimizer As one who spends way too much time cleaning up SQL statements, there is much trivia to be found in guessing how to outsmart the database optimizers. By Chris Rathman at Wed, login or register to post comments So, I still feel like I am So, I still feel like I am missing something; what are the practical benefits of making a language Turing complete?
By Matt M at Wed, login or register to post comments That's Coq Sets in Types, Types in Sets shows more or less that the calculus of constructions with a given number of universes is equivalent to ZFC with some other number of inaccessible cardinals. Or, that Coq is basically such a language and type checking is generally only slow where the automation has produced big terms By Brandon Moore at Wed, login or register to post comments Ya, I actually just read Ya, I actually just read that paper a few months ago.
By Matt M at Wed, login or register to post comments Turing completeness is overrated We can divide computation in two groups: those that are supposed to terminate i. The quality of a language without Turing completeness can be measured by how much work you can do before asking for help ; By Daniel Yokomizo at Wed, login or register to post comments Even theorem provers By dbueno at Thu, login or register to post comments Google is your friend It's from this thread.
By Daniel Yokomizo at Thu, login or register to post comments Google doesn't ignore last names In fact, I did google for it, in several combinations; but all of those had his last name, I guess, so it only found references to this LtU thread.
Ans is ' No ', you have to use javascript to perform addition. Mark i think what you are explaining is a mix between the description of the Universal Turing Machine and Turing Complete. Though it doesn't take consideration for time or storage, as mentioned by others.
Super-brief summary from what Professor Brasilford explains in this video. It has conditional branching i. Also, implies "go to" and thus permitting loop. It gets arbitrary amount of memory e. We call a language Turing-complete if and only if 1 it is decidable by a Turing machine but 2 not by anything less capable than a Turing machine. Truly Turing-complete languages - ones that require the full computing power of Turing machines - are pretty rare. Perhaps the language of strings x.
A common imprecise usage confuses Turing-completeness with Turing-equivalence. Turing-equivalence refers to the property of a computational system which can simulate, and which can be simulated by, Turing machines.
We might say Java is a Turing-equivalent programming language, for instance, because you can write a Turing-machine simulator in Java, and because you could define a Turing machine that simulates execution of Java programs. According to the Church-Turing thesis, Turing machines can perform any effective computation, so Turing-equivalence means a system is as capable as possible if the Church-Turing thesis is true!
Turing equivalence is a much more mainstream concern that true Turing completeness; this and the fact that "complete" is shorter than "equivalent" may explain why "Turing-complete" is so often misused to mean Turing-equivalent, but I digress. In practical language terms familiar to most programmers, the usual way to detect Turing completeness is if the language allows or allows the simulation of nested unbounded while statements as opposed to Pascal-style for statements, with fixed upper bounds.
Consider a player piano roll. The player piano can play a highly complicated piece of music, but there is never any conditional logic in the music. It is not Turing Complete. The piano roll is guaranteed to halt every time. There is no such guarantee for a TM. As Waylon Flinn said :. I believe this is incorrect, a system is Turing complete if it's exactly as powerful as the Turing Machine, i. Can a relational database input latitudes and longitudes of places and roads, and compute the shortest path between them - no.
This is one problem that shows SQL is not Turing complete. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. What is Turing Complete?
Ask Question. Asked 13 years, 3 months ago. Active 7 months ago. Viewed k times. What does the expression "Turing Complete" mean?
Can you give a simple explanation, without going into too many theoretical details? Improve this question. Some very nice links at this SO question. Add a comment. Active Oldest Votes. Here's the briefest explanation: A Turing Complete system means a system in which a program can be written that will find an answer although with no guarantees regarding runtime or memory.
Improve this answer. Mark Harrison Mark Harrison k gold badges silver badges bronze badges. For further reading, see The Annotated Turing. Very approachable. No system is ever Turing-complete in practice, because no realizable system has an infinite tape. What we really mean is that some systems have the ability to approximate Turing-completeness up to the limits of their available memory.
But Vi is the only computational engine ever needed in the world Is Emacs a Turning Machine too? XD — alem0lars. Someone recently showed that PowerPoint is Turing Complete too. Show 6 more comments. This varies according to the scripting technology implemented. For example, the scripting language used in Bitcoin is intentionally designed as Turing Incomplete because it serves its purpose and increased complexity would potentially introduce problems.
By keeping it simple, the developers can predict with high accuracy how it is going to react in the finite number of situations in which it is used. Ethereum, on the other hand, is built as a Turing Complete blockchain. This is important because it needs to understand the agreements which make up smart contracts. If a language is not Turing complete, there are computational problems it cannot solve.
So, purely from a view internal to the language, you can't necessarily do everything you want. If you want to use a non-Turing complete language to design some kind of computer architecture, you'll also run into problems. In order to express or simulate something that is Turing complete, your language needs to also be Turing complete. Python, C, and Java are all Turing Complete, so you can't write compilers for those languages in a language that isn't.
The video games Minecraft and Dwarf fortress can simulate Turing machines, so you can't program those games in a language that isn't Turing complete. Powerpoint slide transitions are Turing complete, so you can't write Microsoft Office in a language that isn't Turing complete, or run it on a system that isn't Turing complete. A programming language that isn't Turing complete isn't a "full programming language" in a sense, and someone who is telling you that a programming language is Turing complete is assuring you that this language can in fact do all of the things that the standard programming languages can.
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