What is undecidability - Mathematics Stack Exchange
What does it mean that some problem is undecidable? For instance the halting problem. Does it mean that humans can never invent a new technique that always decides whether a turing …
Help understanding the proof that $L = \ { \langle M \rangle \mid …
Dec 8, 2023 · Help understanding the proof that $L = \ { \langle M \rangle \mid M \text { is a TM that accepts the input string } 101\}$ is undecidable Ask Question Asked 2 years ago Modified …
computational complexity - Are all undecidable problems NP-Hard ...
So, I need the answer to the question in the title: Are all undecidable problems NP-hard? If I have some undecidable problem (for example, Post correspondence problem), can I say it's NP …
context free grammar - Prove that $OVERLAP_ {CFG}$ is …
Dec 7, 2023 · Prove that $OVERLAP_ {CFG}$ is undecidable Ask Question Asked 2 years ago Modified 2 years ago
Is there a statement whose undecidability is undecidable?
Aug 18, 2015 · Thus the undecidability of S is decidable which contradicts the assumption that the undecidability of S is undecidable. Thus for any statement S, if its undecidability is …
logic - Are non-computable and undecidable the same?
May 2, 2017 · 8 In the context of computability theory, there is no difference between a non-computable set and an undecidable set. The term "undecidable" is also used in logic to refer to …
Why is Peano arithmetic undecidable? - Mathematics Stack …
28 I read that Presburger arithmetic is decidable while Peano arithmetic is undecidable. Peano arithmetic extends Presburger arithmetic just with the addition of the multiplication operator. …
What is the relationship between the number of undecidable …
Apr 13, 2025 · So paradoxically, increasing the strength of the system might increase the overall number of undecidable statements. If that’s the case, then even if we tried to eliminate …
soft question - What would be the consequences if we assume …
Oct 20, 2024 · In practice, most mathematicians and computer scientists adopt a pragmatic stance toward undecidable questions. Even if a statement like P=NP were proven to be …
proof verification - Proving Undecidability of first order logic ...
Mar 3, 2014 · The proposition "first order logic is undecidable" is, when unpacked, just a proposition of the form "there is no computable function which does so-and-so". So of course a …