Re: [Theory] Halting problem

2010-10-13 Thread Stewart Gordon
On 13/10/2010 00:23, %u wrote: snip Yep, it needs to run in a minimal 2^n larger limited memory system (n2^n that is). But those two system could of course be on the same computer. My computer, for instance, can run Halt.exe on 30bit programs :D n2^n? Are you sure? Here's how I worked it

Re: [Theory] Halting problem

2010-10-13 Thread %u
== Quote from Stewart Gordon (smjg_1...@yahoo.com)'s article On 13/10/2010 00:23, %u wrote: snip Yep, it needs to run in a minimal 2^n larger limited memory system (n2^n that is). But those two system could of course be on the same computer. My computer, for instance, can run

Re: [Theory] Halting problem

2010-10-13 Thread Manfred_Nowak
Stewart Gordon wrote: to do it for a setup with n bits of memory, the halt analyser would need 2^n bits. Depends on how you define memory. If registers and flags of the CPU are not included in your definition of memory, then 2^n bits may not suffice. -manfred

Re: [Theory] Halting problem

2010-10-13 Thread Simen kjaeraas
Manfred_Nowak svv1...@hotmail.com wrote: Stewart Gordon wrote: to do it for a setup with n bits of memory, the halt analyser would need 2^n bits. Depends on how you define memory. If registers and flags of the CPU are not included in your definition of memory, then 2^n bits may not

Re: [Theory] Halting problem

2010-10-13 Thread Stewart Gordon
On 13/10/2010 14:17, Manfred_Nowak wrote: Stewart Gordon wrote: to do it for a setup with n bits of memory, the halt analyser would need 2^n bits. Depends on how you define memory. If registers and flags of the CPU are not included in your definition of memory, then 2^n bits may not suffice.

Re: [Theory] Halting problem

2010-10-12 Thread BCS
Hello %u, Just to be clear about this, the halting problem is only unsolvable for Turing machines. More correctly, the halting problem for machine X is unsolvable by machine X (or any weaker machine). -- ... IXOYE

Re: [Theory] Halting problem

2010-10-12 Thread %u
== Quote from BCS (n...@anon.com)'s article Hello %u, Just to be clear about this, the halting problem is only unsolvable for Turing machines. More correctly, the halting problem for machine X is unsolvable by machine X (or any weaker machine). I was looking for a way out by making

Re: [Theory] Halting problem

2010-10-12 Thread Norbert Nemec
On 10/10/2010 09:16 PM, %u wrote: Basically: because 1GB=infinity for all purposes of logical reasoning. No no no! :D If you'd left out logical it would have been just fine :D I'm not even going to give ridiculous logical proof with this assumption.. no I will not.. .. assume inf is 1GB.. No!

Re: [Theory] Halting problem

2010-10-12 Thread Stewart Gordon
On 09/10/2010 18:58, %u wrote: Just to be clear about this, the halting problem is only unsolvable for Turing machines. snip No, it's unsolvable for any computational class that's at least as powerful as a Turing machine. In its most general form, the unsolvability theorem states that,

Re: [Theory] Halting problem

2010-10-12 Thread Stewart Gordon
On 09/10/2010 18:58, %u wrote: snip In the more general limited-memory setup it is actually quite simple to solve the Halting problem: 1. Save every state of the system. 2. If the program ends, the program Halts - done. 2. For every state, check to if it has been saved before. If so, the

Re: [Theory] Halting problem

2010-10-12 Thread %u
== Quote from Stewart Gordon (smjg_1...@yahoo.com)'s article On 09/10/2010 18:58, %u wrote: snip In the more general limited-memory setup it is actually quite simple to solve the Halting problem: 1. Save every state of the system. 2. If the program ends, the program Halts - done.

Re: [Theory] Halting problem

2010-10-10 Thread Norbert Nemec
Impossible to solve is often used synonymous to exponentially hard to solve meaning, as the problem size (e.g. size of finite memory) grows as N, the cost for solution grows as exp(N). Of course, the actual cost of an actual problem always depends on the pre-factor, but experience shows that

Re: [Theory] Halting problem

2010-10-10 Thread Justin Johansson
On 10/10/2010 8:07 PM, Norbert Nemec wrote: Impossible to solve is often used synonymous to exponentially hard to solve meaning, as the problem size (e.g. size of finite memory) grows as N, the cost for solution grows as exp(N). Of course, the actual cost of an actual problem always depends on

Re: [Theory] Halting problem

2010-10-10 Thread %u
I am not sure where exactly the line lies where people tend to use impossible as a synonym for a hard problem, but I agree that np might well be around that border. It depends on trivial, but I wouldn't call integer factorization impossible. The point I was trying to make was that using

Re: [Theory] Halting problem

2010-10-10 Thread Norbert Nemec
On 10/10/10 17:06, %u wrote: I am not sure where exactly the line lies where people tend to use impossible as a synonym for a hard problem, but I agree that np might well be around that border. It depends on trivial, but I wouldn't call integer factorization impossible. The point I was trying

Re: [Theory] Halting problem

2010-10-10 Thread %u
== Quote from Norbert Nemec (norb...@nemec-online.de)'s article On 10/10/10 17:06, %u wrote: I am not sure where exactly the line lies where people tend to use impossible as a synonym for a hard problem, but I agree that np might well be around that border. It depends on trivial, but

Re: [Theory] Halting problem

2010-10-10 Thread Norbert Nemec
On 10/10/10 19:36, %u wrote: == Quote from Norbert Nemec (norb...@nemec-online.de)'s article In language design, the theoretical halting problem actually is often an argument because the compiler does not know the memory limitation at run time. The finite memory of the machine can therefore not

Re: [Theory] Halting problem

2010-10-10 Thread %u
== Quote from Norbert Nemec (norb...@nemec-online.de)'s article On 10/10/10 19:36, %u wrote: == Quote from Norbert Nemec (norb...@nemec-online.de)'s article In language design, the theoretical halting problem actually is often an argument because the compiler does not know the memory

[Theory] Halting problem

2010-10-09 Thread %u
Just to be clear about this, the halting problem is only unsolvable for Turing machines. That is, a machine with a tape that extends or is indefinitely extensible to the right.[wikipedia:Turing machine] In the more general limited-memory setup it is actually quite simple to solve the Halting

Re: [Theory] Halting problem

2010-10-09 Thread Simen kjaeraas
%u e...@ee.com wrote: Just to be clear about this, the halting problem is only unsolvable for Turing machines. That is, a machine with a tape that extends or is indefinitely extensible to the right.[wikipedia:Turing machine] In the more general limited-memory setup it is actually quite

Re: [Theory] Halting problem

2010-10-09 Thread %u
== Quote from Simen kjaeraas (simen.kja...@gmail.com)'s article %u e...@ee.com wrote: Just to be clear about this, the halting problem is only unsolvable for Turing machines. That is, a machine with a tape that extends or is indefinitely extensible to the right.[wikipedia:Turing