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6 votes
2 answers
276 views

Extending polynomial hierarchy above $\omega$

The arithmetic hierarchy is naturally extended to all ordinals via ordinal notations creating a hierarchy for all hyperarithmetic sets. The polynomial time hierarchy is defined analogously to the ...
Peter Gerdes's user avatar
  • 3,029
3 votes
0 answers
146 views

Lower Bound of Solutions to P=NP?

Do we at least know that simulating polynomial time non-deterministic Turing machines requires more than a linear slowdown? That is, do we know there is some non-deterministic Turing machine with ...
Peter Gerdes's user avatar
  • 3,029
13 votes
3 answers
834 views

Undecidable infinite analogs of NP-complete problems?

In the paper Some undecidable problems involving edge-coloring of graphs, Burr proves that a certain k-coloring problems for certain infinite graphs (however, with finite descriptions - here "...
15 votes
2 answers
2k views

How did the Baker-Gill-Solovay paper come to be?

How did the Baker-Gill-Solovay paper come to be? Why were those three people talking together about "Relativizations of the $P=?NP$" question, and what was their collaboration like for the ...
user avatar
4 votes
1 answer
248 views

Constructing hard inputs for the complement of bounded halting

If there is always a hard input for the complement of bounded halting, can that input be constructed? More precisely, suppose that for any deterministic TM $M$ accepting $$ \text{coBHP}=\{\...
Hunter Monroe's user avatar
22 votes
5 answers
5k views

Why relativization can't solve NP !=P?

If this problem is really stupid, please close it. But I really wanna get some answer for it. And I learnt computational complexity by reading books only. When I learnt to the topic of relativization ...
Ross Tang's user avatar
  • 581
2 votes
0 answers
2k views

Quantum computation implications of (P vs NP) [duplicate]

Possible Duplicate: What impact would P!=NP have on the characterization of BQP? Before I begin, I had a similar post closed for mentioning the recently released (to be verified) proof that P!=...
user8347's user avatar
  • 267
12 votes
2 answers
3k views

What impact would P!=NP have on the characterization of BQP?

Many complexity theorists assume that $P\ne NP.$ If this is proved, how would it impact quantum computing and quantum algorithms? Would the proof immediately disallow quantum algorithms from ever ...
user8347's user avatar
  • 267
31 votes
3 answers
3k views

Given a polynomial-time algorithm, can we compute an explicit polynomial time bound just from the program?

Question. Given a Turing-machine program $e$, which is guaranteed to run in polynomial time, can we computably find such a polynomial? In other words, is there a computable function $e\mapsto p_e$, ...
Joel David Hamkins's user avatar