Search Results: PSPACE (complexity)
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PSPACE
Senin, 2026-06-08 14:32:42{\mathsf {P{\overset {?}{=}}PSPACE}}} More unsolved problems in computer science In computational complexity theory, PSPACE is the set of all decision...
Click to read more »PSPACE-complete
Jumat, 2026-01-02 19:21:50In computational complexity theory, a decision problem is PSPACE-complete if it can be solved using an amount of memory that is polynomial in the input...
Click to read more »IP (complexity)
Rabu, 2026-05-06 23:21:35problems solvable by an interactive proof system. It is equal to the class PSPACE. The result was established in a series of papers: the first by Lund, Karloff...
Click to read more »QIP (complexity)
Jumat, 2026-03-20 07:45:00is contained in PSPACE, which also proves that QIP = IP = PSPACE, since PSPACE is easily shown to be in QIP using the result IP = PSPACE. Watrous, John...
Click to read more »Polynomial hierarchy
Senin, 2026-05-25 21:40:36the classes NP and co-NP. Each class in the hierarchy is contained within PSPACE. The hierarchy can be defined using oracle machines or alternating Turing...
Click to read more »P (complexity)
Minggu, 2026-01-18 10:36:55than PSPACE, the class of problems decidable in polynomial space. PSPACE is equivalent to NPSPACE by Savitch's theorem. Again, whether P = PSPACE is an...
Click to read more »Computational complexity theory
Selasa, 2026-08-11 22:17:17PSPACE {\displaystyle {\textsf {P}}\subseteq {\textsf {NP}}\subseteq {\textsf {PP}}\subseteq {\textsf {PSPACE}}} , but it is possible that P = PSPACE...
Click to read more »Complexity class
Rabu, 2026-08-12 15:32:40complexity classes relate to each other in the following way: L⊆NL⊆P⊆NP⊆PSPACE⊆EXPTIME⊆NEXPTIME⊆EXPSPACE Where ⊆ denotes the subset relation. However,...
Click to read more »P versus NP problem
Rabu, 2026-08-12 02:11:40prove that IP = PSPACE. However, in 2008, Scott Aaronson and Avi Wigderson showed that the main technical tool used in the IP = PSPACE proof, known as...
Click to read more »John Watrous (computer scientist)
Kamis, 2026-07-16 01:42:25interactive proofs, and the quantum analogue of the celebrated result IP = PSPACE: QIP = PSPACE. This was preceded by a series of results, showing QIP can be constrained...
Click to read more »EXPTIME
Senin, 2025-08-25 22:00:42basic time and space complexity classes in the following way: P ⊆ NP ⊆ PSPACE ⊆ EXPTIME ⊆ NEXPTIME ⊆ EXPSPACE. Furthermore, by the time hierarchy theorem...
Click to read more »Checkers
Kamis, 2026-07-23 05:41:03the drawing rule in standard Checkers), then the problem is in PSPACE, thus it is PSPACE-complete. However, without this bound, Checkers is EXPTIME-complete...
Click to read more »Go and mathematics
Jumat, 2026-06-26 05:39:34complexity. Without ko, Go is PSPACE-hard. This is proved by reducing True Quantified Boolean Formula, which is known to be PSPACE-complete, to generalized...
Click to read more »Mahjong solitaire
Jumat, 2026-06-19 06:27:20removing all tiles is PSPACE-complete, and the game is NP-complete if looking below tiles is allowed. It has been proven that it is PSPACE-hard to approximate...
Click to read more »BPP (complexity)
Senin, 2026-04-27 21:23:24are strict subsets, since we don't even know if P is a strict subset of PSPACE. BPP is contained in the second level of the polynomial hierarchy and therefore...
Click to read more »BQP
Selasa, 2026-02-24 19:28:01PP\subseteq PSPACE\subseteq EXP}}} As the problem of P = ? P S P A C E {\displaystyle {\mathsf {P}}\ {\stackrel {?}{=}}\ {\mathsf {PSPACE}}} has...
Click to read more »Lance Fortnow
Kamis, 2026-08-13 00:12:52work was hardly two weeks old when Adi Shamir employed it to prove that IP=PSPACE. Quickly following up on this (January 17, 1990, less than two months after...
Click to read more »Descriptive complexity theory
Kamis, 2026-08-20 22:25:01Second-order logic with a transitive closure operator (commutative or not) yields PSPACE, the problems solvable in polynomial space. Second-order logic with a least...
Click to read more »Lists of problems
Rabu, 2026-08-12 13:53:13mathematics List of undecidable problems List of NP-complete problems List of PSPACE-complete problems List of problems in loop theory and quasigroup theory...
Click to read more »NP (complexity)
Kamis, 2026-08-13 09:40:18ignoring the proof and solving it. NP is contained in PSPACE—to show this, it suffices to construct a PSPACE machine that loops over all proof strings and feeds...
Click to read more »List of PSPACE-complete problems
Selasa, 2025-12-09 15:31:30Here are some of the more commonly known problems that are PSPACE-complete when expressed as decision problems. This list is in no way comprehensive. Generalized...
Click to read more »Hex (board game)
Sabtu, 2026-08-01 03:27:251145/321978.321989. S2CID 8845949. Stefan Reisch (1981). "Hex ist PSPACE-vollständig (Hex is PSPACE-complete)". Acta Informatica. 15 (2): 167–191. doi:10.1007/bf00288964...
Click to read more »Co-NP
Sabtu, 2026-05-30 03:53:22 is symmetrical. co-NP is a subset of PH, which itself is a subset of PSPACE. An example of a problem that is known to belong to both NP and co-NP (but...
Click to read more »Dots and boxes
Senin, 2026-08-17 07:14:30complicates the analysis considerably. Playing Dots and Boxes optimally is PSPACE-complete. Dots and Boxes need not be played on a rectangular grid – it can...
Click to read more »Ghost (game)
Minggu, 2026-07-12 09:32:27is in EXPSPACE, and is PSPACE-hard. It's proved to be PSPACE-hard by reducing Generalized Geography, a problem known to be PSPACE-hard, to a game of Ghost...
Click to read more »Game complexity
Sabtu, 2026-06-27 13:47:07need not store game states; however many games of interest are known to be PSPACE-hard, and it follows that their space complexity will be lower-bounded by...
Click to read more »QMA
Senin, 2026-08-10 19:03:58in PSPACE. It is unknown if any of these inclusions is unconditionally strict, as it is not even known whether P is strictly contained in PSPACE or P...
Click to read more »Generalized geography
Selasa, 2026-03-10 04:12:05computational complexity theory, generalized geography is a well-known PSPACE-complete problem. Geography is a children's game, where players take turns...
Click to read more »Interactive proof system
Rabu, 2026-05-27 06:26:53exponential time, a very large class. NEXPTIME contains PSPACE, and is believed to strictly contain PSPACE. Adding a constant number of additional provers beyond...
Click to read more »NP-hardness
Rabu, 2026-06-17 21:44:00polynomial space, but not in non-deterministic polynomial time (unless NP = PSPACE). NP-hard problems do not have to be elements of the complexity class NP...
Click to read more »Nondeterministic Turing machine
Minggu, 2026-08-09 00:57:07solution among the exponentially many branches. Probabilistic Turing machine PSPACE Garey, Michael R.; David S. Johnson (1979). Computers and Intractability:...
Click to read more »Rush Hour (puzzle)
Jumat, 2025-08-15 10:27:14solution is PSPACE-complete. This is proved by reducing a graph game called nondeterministic constraint logic, which is known to be PSPACE-complete, to...
Click to read more »Reversi
Sabtu, 2026-07-25 19:57:05determining if the first player has a winning move in a given position is PSPACE-complete. The World Othello Championship (WOC), which started in 1977, was...
Click to read more »Quantum computing
Kamis, 2026-08-20 19:05:26P, NP, and PSPACE is not known. However, it is known that P ⊆ B Q P ⊆ P S P A C E {\displaystyle {\mathsf {P\subseteq BQP\subseteq PSPACE}}} ; that is...
Click to read more »True quantified Boolean formula
Sabtu, 2026-07-25 04:15:49\exists z\ ((x\lor z)\land y)} QBF is the canonical complete problem for PSPACE, the class of problems solvable by a deterministic or nondeterministic Turing...
Click to read more »Generalized game
Senin, 2025-07-21 14:36:21win for the first player in a given position is PSPACE-complete. Generalized hex and reversi are PSPACE-complete. For many generalized games which may...
Click to read more »Ultrafinitism
Rabu, 2026-06-17 01:24:05capture mathematics associated with various complexity classes like P and PSPACE. Buss's work can be considered the continuation of Edward Nelson's work...
Click to read more »Space complexity
Minggu, 2026-08-16 11:51:39use O ( f ( n ) ) {\displaystyle O(f(n))} space. The complexity classes PSPACE and NPSPACE allow f {\displaystyle f} to be any polynomial, analogously...
Click to read more »Circuits over sets of natural numbers
Rabu, 2025-08-13 06:38:58in co-RP in DLOGCFL +,× P-complete in DLOGCFL ∪,∩,−,+ PSPACE-complete PSPACE-complete ∪,∩,+ PSPACE-complete NP-complete ∪,+ NP-complete NP-complete ∩,+...
Click to read more »PP (complexity)
Selasa, 2026-08-18 19:18:09are uniform (generated by a polynomial-time algorithm). PP is included in PSPACE. This can be easily shown by exhibiting a polynomial-space algorithm for...
Click to read more »Reconfiguration
Minggu, 2026-02-01 08:22:12complexity can be higher; in particular, testing reachability for Sokoban is PSPACE-complete. Rotation distance in binary trees and related problems of flip...
Click to read more »Adi Shamir
Senin, 2026-07-13 20:30:33Lance Fortnow, Howard Karloff, and Noam Nisan, that the complexity classes PSPACE and IP are equal. 1983 – Erdős Prize of the Israel Mathematical Society...
Click to read more »Quantum complexity theory
Senin, 2026-08-10 19:15:06classes relate to classical complexity classes such as P, NP, BPP, and PSPACE. One of the reasons quantum complexity theory is studied are the implications...
Click to read more »Intersection non-emptiness problem
Selasa, 2026-06-02 04:30:22intersection problem or the non-emptiness of intersection problem, is a PSPACE-complete decision problem from the field of automata theory. The problem...
Click to read more »Gomoku
Kamis, 2026-07-09 06:23:063233/ICG-2001-24104. S2CID 207577292. Stefan Reisch (1980). "Gobang ist PSPACE-vollständig (Gomoku is PSPACE-complete)". Acta Informatica. 13: 59–66. doi:10.1007/bf00288536...
Click to read more »EXPSPACE
Selasa, 2026-04-14 08:09:42of as the hardest problems in EXPSPACE. EXPSPACE is a strict superset of PSPACE, NP, and P. It contains EXPTIME and is believed to strictly contain it,...
Click to read more »Polynomial-time reduction
Jumat, 2026-05-01 17:58:38computational problem that is known to be NP-hard and in PSPACE, but is not known to be complete for NP, PSPACE, or any language in the polynomial hierarchy. ∃...
Click to read more »Integer circuit
Selasa, 2021-07-06 13:51:02LOGCFL +,× P-hard, in co-NP L-hard, in LOGCFL ∪,∩,−,+ PSPACE-complete PSPACE-complete ∪,∩,+ PSPACE-complete NP-complete ∪,+ NP-complete NP-complete ∩,+...
Click to read more »Simon's problem
Jumat, 2026-03-20 15:31:21cannot easily be proven, since this would prove that P is different from PSPACE. Simon's problem considers access to a function f : { 0 , 1 } n → { 0 ,...
Click to read more »Game of the Amazons
Jumat, 2026-07-03 20:57:16configuration) is PSPACE-complete. This can be proved in two ways. The first way is by reducing a generalized Hex position, which is known to be PSPACE-complete...
Click to read more »List of unsolved problems in computer science
Sabtu, 2026-03-28 00:59:15NC = P problem NP = co-NP problem P = BPP problem P = PSPACE problem L = NL problem PH = PSPACE problem L = P problem L = RL problem Unique games conjecture...
Click to read more »AP
Minggu, 2026-08-09 01:26:52airframe and powerplant ratings AP, an alternative characterization of PSPACE In computational complexity theory Application Processor, usually means...
Click to read more »NFA minimization
Rabu, 2026-07-08 18:14:34minimization is PSPACE-complete. No efficient (polynomial time) algorithms are known, and under the standard assumption that P ≠ PSPACE, none exist. The...
Click to read more »Nondeterministic constraint logic
Selasa, 2026-04-07 03:18:18proven to be PSPACE-complete. These hardness results form the basis for proofs that various games and puzzles are PSPACE-hard or PSPACE-complete. In the...
Click to read more »Fixed-point logic
Jumat, 2026-04-24 23:09:36structures, a property is expressible in FO(PFP,X) if and only if it lies in PSPACE. Since the iterated predicates involved in calculating the partial fixed...
Click to read more »P/poly
Selasa, 2026-01-20 05:44:53furthermore, NP ⊆ P/poly implies AM = MA If PSPACE ⊆ P/poly then P S P A C E = Σ 2 P ∩ Π 2 P {\displaystyle {\mathsf {PSPACE}}=\Sigma _{2}^{\mathsf {P}}\cap \Pi...
Click to read more »ZPP (complexity)
Selasa, 2026-08-18 19:28:00other probabilistic complexity classes (RP, co-RP, BPP, BQP, PP), which generalise P within PSPACE. It is unknown if any of these containments are strict....
Click to read more »Zero-knowledge proof
Kamis, 2026-08-13 10:53:16unbreakable encryption, there are zero-knowledge proofs for all problems in IP = PSPACE, or in other words, anything that can be proven by an interactive proof...
Click to read more »Distributed computing
Rabu, 2026-08-12 02:28:49non-deterministic) finite-state machines can reach a deadlock. This problem is PSPACE-complete, i.e., it is decidable, but not likely that there is an efficient...
Click to read more »Circuit (computer science)
Rabu, 2025-04-16 00:48:03ISBN 978-3-540-64310-4. Yang, Ke (2001). "Integer Circuit Evaluation Is PSPACE-Complete". Journal of Computer and System Sciences. 63 (2, September 2001):...
Click to read more »Instant Insanity
Minggu, 2026-08-09 23:16:30proved that this game is PSPACE-complete, which illustrates the observation that NP-complete puzzles tend to lead to PSPACE-complete games. Devil's Dice...
Click to read more »Existential theory of the reals
Sabtu, 2026-01-31 01:27:32semialgebraic set is non-empty. This decision problem is NP-hard and lies in PSPACE, giving it significantly lower complexity than Alfred Tarski's quantifier...
Click to read more »Boolean satisfiability problem
Jumat, 2026-08-14 06:56:43Boolean formula problem (QBF), which can be shown to be PSPACE-complete. It is widely believed that PSPACE-complete problems are strictly harder than any problem...
Click to read more »Second-order logic
Rabu, 2026-08-12 22:16:11formulas. PH is the set of languages definable by second-order formulas. PSPACE is the set of languages definable by second-order formulas with an added...
Click to read more »Havannah (board game)
Senin, 2026-04-13 15:40:25board. During this competition the pie rule is used. Solving Havannah is PSPACE-complete with respect to the size of the input graph. The proof is by a...
Click to read more »Kōnane
Rabu, 2026-07-01 08:45:32player eventually cannot perform a capture. Bob Hearn proved that Kōnane is PSPACE-complete with respect to the dimensions of the board, by a reduction from...
Click to read more »Simplex algorithm
Rabu, 2026-08-12 09:31:57computing its output is PSPACE-complete. In 2015, this was strengthened to show that computing the output of Dantzig's pivot rule is PSPACE-complete. Analyzing...
Click to read more »RP (complexity)
Minggu, 2026-01-18 10:58:54probabilistic complexity classes (ZPP, co-RP, BPP, BQP, PP), which generalise P within PSPACE. It is unknown if any of these containments are strict....
Click to read more »Nash equilibrium computation
Rabu, 2026-08-12 16:23:50that the problem of finding a PNE reachable from a given input state is PSPACE-complete. The class of ordinal potential games is even larger than the class...
Click to read more »Context-sensitive grammar
Selasa, 2026-08-11 10:08:05context-sensitive grammar G, is PSPACE-complete. Moreover, there are context-sensitive grammars whose languages are PSPACE-complete. In other words, there...
Click to read more »TwixT
Rabu, 2026-04-29 23:33:38player can achieve this, the game is a draw. TwixT has been proven to be PSPACE-complete for determining the game value, via a reduction from Hex. TwixT...
Click to read more »Carsten Lund
Kamis, 2026-05-28 18:21:18Foundations of Computer Science characterizing complexity classes such as PSPACE and NEXPTIME in terms of interactive proof systems; this work became part...
Click to read more »Alternating finite automaton
Rabu, 2026-02-11 19:20:08equivalence problem (do two input AFAs recognize the same language) are PSPACE-complete for AFAs. Chandra, Ashok K.; Kozen, Dexter C.; Stockmeyer, Larry...
Click to read more »Regular language
Minggu, 2026-08-16 05:03:30already for a singleton alphabet. For larger alphabets, that problem is PSPACE-complete. If regular expressions are extended to allow also a squaring operator...
Click to read more »Referential integrity
Kamis, 2025-08-28 00:20:35axiomatized by inference rules and can be decided by a PSPACE algorithm. The problem can be shown to be PSPACE-complete by reduction from the acceptance problem...
Click to read more »Space hierarchy theorem
Senin, 2026-06-29 22:13:08required, but runs for infinite time. The above proof holds for the case of PSPACE, but some changes need to be made for the case of NPSPACE. The crucial point...
Click to read more »Michael Sipser
Selasa, 2026-04-14 19:24:44With fellow graduate student David Lichtenstein, Sipser proved that Go is PSPACE hard. In quantum computation theory, he introduced the adiabatic algorithm...
Click to read more »Counting hierarchy
Minggu, 2025-12-28 23:18:24C2P = PPPP C3P = PPPPPP ... The counting hierarchy is contained within PSPACE. By Toda's theorem, the polynomial hierarchy PH is entirely contained in...
Click to read more »Cook–Levin theorem
Jumat, 2026-08-21 09:09:18a problem (the recognition of true quantified Boolean formulas) that is PSPACE-complete. Analogously, dependency quantified boolean formulas encode computation...
Click to read more »James Renegar
Selasa, 2025-03-18 07:45:45S2CID 206798056. 1988(over 740 citations) Regenar, James (April 1988). "A faster PSPACE algorithm for deciding the existential theory of the reals" (PDF). Technical...
Click to read more »Random oracle
Rabu, 2025-10-22 22:12:09later shown to be false, as the two acceptable complexity classes IP and PSPACE were shown to be equal despite IPA ⊊ PSPACEA for a random oracle A with...
Click to read more »Savitch's theorem
Jumat, 2026-02-27 04:14:53the Turing machine. Some important corollaries of the theorem include: PSPACE = NPSPACE That is, the languages that can be recognized by deterministic...
Click to read more »Col (game)
Senin, 2025-07-07 02:58:19the outcome in Snort is PSPACE-complete on general graphs. This is proven by reducing partizan node Kayles, which is PSPACE-complete, to a game of Snort...
Click to read more »Turing Tumble
Sabtu, 2026-08-08 08:24:20follows because the game is P-complete by the circuit value problem and PSPACE-complete if an exponential number of marbles is allowed. The device has...
Click to read more »Zero–one law (logic)
Rabu, 2026-07-15 03:11:15{\displaystyle \mu (\varphi )=0} . Moreover this problem has been shown to be PSPACE-complete. The following logics have the zero-one law: First-order logic...
Click to read more »Shannon switching game
Rabu, 2026-02-25 09:15:58otherwise, Cut can win. Unlike some other connection games, which can be PSPACE hard, optimal moves for the undirected switching game can be found in polynomial...
Click to read more »Phutball
Selasa, 2025-11-11 01:59:22center, determining whether the current player has a winning strategy is PSPACE-hard. Schmittberger, R. Wayne (1992). New Rules for Classic Games. John...
Click to read more »Poset game
Senin, 2024-10-07 11:21:05Deciding the winner of an arbitrary finite poset game is PSPACE-complete. This means that unless P=PSPACE, computing the Grundy value of an arbitrary poset game...
Click to read more »Graph coloring game
Kamis, 2025-11-27 10:48:18interesting open problem". Only in 2020 it was proved that the game is PSPACE-Complete. Acyclic coloring. Every graph G {\displaystyle G} with acyclic...
Click to read more »Transdichotomous model
Senin, 2025-09-01 13:33:09models with unlimited precision are unreasonably powerful (able to solve PSPACE-complete problems in polynomial time). The transdichotomous model makes...
Click to read more »Hypercomputation
Jumat, 2025-12-19 00:30:30inside the black hole. Access to a CTC may allow the rapid solution to PSPACE-complete problems, a complexity class which, while Turing-decidable, is...
Click to read more »N-body simulation
Kamis, 2026-04-09 10:22:03poly(n) is in PSPACE. On the other hand, if the question is whether the body eventually reaches the destination ball, the problem is PSPACE-hard. These...
Click to read more »Karp–Lipton theorem
Selasa, 2026-08-11 02:23:18collapses to SP 2 complexity class. There are stronger conclusions possible if PSPACE, or some other complexity classes are assumed to have polynomial-sized circuits;...
Click to read more »Many-one reduction
Selasa, 2025-10-07 23:22:37under some type of many-one reducibility, including P, NP, L, NL, co-NP, PSPACE, EXP, and many others. It is known for example that the first four listed...
Click to read more »Maker-Breaker game
Kamis, 2026-04-23 01:23:42Maker-Breaker game called an Avoider-Enforcer game. Maker-Breaker game is PSPACE-complete even if the size of each set is restricted to 5. The first result...
Click to read more »Linear logic
Selasa, 2026-08-11 23:25:56multiplicatives and additives (i.e., exponential-free). MALL entailment is PSPACE-complete. Multiplicative-exponential linear logic (MELL): only multiplicatives...
Click to read more »Japaridze's polymodal logic
Kamis, 2025-07-03 07:25:13to the class of all GLP-spaces. The problem of being a theorem of GLP is PSPACE-complete. So is the same problem restricted to only variable-free formulas...
Click to read more »Sokoban
Kamis, 2026-07-23 03:12:27any given Sokoban puzzle is solvable is a problem known to be NP-hard and PSPACE-complete. In artificial intelligence research, Sokoban serves as an experimental...
Click to read more »Logic of graphs
Selasa, 2026-04-21 01:04:24sentence has probability tending to zero or to one is high: the problem is PSPACE-complete. If a first-order graph property has probability tending to one...
Click to read more »Ray tracing (graphics)
Jumat, 2026-08-14 10:24:08reflective objects represented by a system of rational linear inequalities is PSPACE-hard. For any dimension equal to or greater than 2, ray tracing with a finite...
Click to read more »Online algorithm
Kamis, 2026-08-13 09:52:16between the online and offline algorithms' performance. This problem is PSPACE-complete. There are many formal problems that offer more than one online...
Click to read more »Joos Ulrich Heintz
Minggu, 2026-03-15 00:13:35reasonable geometric (not algebraic) computation problems are solvable in PSPACE. Later, he extended these complexity results to polynomial input systems...
Click to read more »Closed timelike curve
Minggu, 2026-08-16 12:18:06implies also equivalence of quantum and classical computation (both in PSPACE). If Lloyd's prescription holds, quantum computations would be PP-complete...
Click to read more »Canadian traveller problem
Minggu, 2026-04-26 22:25:46original paper analysed the complexity of the problem and reported it to be PSPACE-complete. It was also shown that finding an optimal path in the case where...
Click to read more »Giorgi Japaridze
Jumat, 2026-06-19 11:33:34link]". Logic Journal of the IGPL 22 (2014), pages 982-991. I. Shapirovsky, "PSPACE-decidability of Japaridze's polymodal logic". Advances in Modal Logic 7...
Click to read more »Deterministic finite automaton
Kamis, 2026-07-23 14:37:20solved efficiently also for NFAs. The non-universality problem for NFAs is PSPACE complete since there are small NFAs with shortest rejecting word in exponential...
Click to read more »Ryan Williams (computer scientist)
Minggu, 2026-05-03 22:49:58Valiant, and strengthening the case in the negative for the question if PSPACE=P. Ryan Williams is married to Virginia Vassilevska Williams, also a theoretical...
Click to read more »Lemke–Howson algorithm
Selasa, 2025-10-07 17:04:42pure strategies in the game. Subsequently, it has been shown that it is PSPACE-complete to find any of the solutions that can be obtained with the Lemke–Howson...
Click to read more »Reduction (complexity)
Kamis, 2025-12-11 01:38:14classes P, NP and PSPACE are closed under (many-one, "Karp") polynomial-time reductions. The complexity classes L, NL, P, NP and PSPACE are closed under...
Click to read more »Randomized algorithm
Rabu, 2026-08-12 03:48:55all-powerful prover and a verifier that implements a BPP algorithm. IP = PSPACE. However, if it is required that the verifier be deterministic, then IP...
Click to read more »Context-sensitive language
Kamis, 2025-11-06 15:46:53grammar, or by an arbitrary deterministic context-sensitive grammar, is a PSPACE-complete problem. List of parser generators for context-sensitive languages...
Click to read more »Emptiness problem
Senin, 2025-09-29 01:52:07question, such as the emptiness problem for non-erasing stack automata, are PSPACE-complete. The emptiness problem in machine learning and formal languages...
Click to read more »Entscheidungsproblem
Senin, 2026-05-11 02:56:31) {\displaystyle {\rm {{Sat}([\exists ^{n}\forall \exists ]_{=})}}} are PSPACE-complete (Section 5.4.3). Börger et al. (2001) describes the level of computational...
Click to read more »Lemmings (video game)
Selasa, 2026-06-09 09:03:20Lemmings is NP-hard. Later, Giovanni Viglietta showed that the task is PSPACE-complete, even for levels where there is only one lemming to save. In 2010...
Click to read more »Solved game
Senin, 2026-08-17 13:33:11solving Hex on an N×N board is unlikely as the problem has been shown to be PSPACE-complete.[citation needed] If Hex is played on an N×(N + 1) board then the...
Click to read more »PCTC
Senin, 2026-01-05 21:05:47closed timelike curves, a computational complexity class equal in power to PSPACE Pure Car and Truck Carrier, a type of roll-on/roll-off cargo ship designed...
Click to read more »Computer Go
Kamis, 2026-01-15 12:03:58Wolfe in their book Mathematical Go. Go endgames have been proven to be PSPACE-hard if the absolute best move must be calculated on an arbitrary mostly...
Click to read more »Strategy-stealing argument
Rabu, 2026-05-27 11:04:18Ofer Grossman proved that the problem of finding a winning strategy is PSPACE-hard in two kinds of games in which strategy-stealing arguments were used:...
Click to read more »Square-root sum problem
Selasa, 2026-05-05 06:04:18Miltersen prove that SRS lies in the counting hierarchy (which is contained in PSPACE). Specifically, they show that SRS lies in PPPPPPP, in the fourth level...
Click to read more »Kayles
Jumat, 2025-11-14 19:05:36wins), Schaefer proved in 1978 that deciding the outcome of these games is PSPACE-complete (the same holds for the partisan versions, in which, for every...
Click to read more »List of complexity classes
Sabtu, 2026-06-13 02:21:04building up arithmetic functions. PSPACE Solvable with polynomial space. PSPACE-complete The hardest problems in PSPACE. PTAS Polynomial-time approximation...
Click to read more »Travelling salesman problem
Jumat, 2026-08-14 01:26:30Euclidean TSP is known to be in the Counting Hierarchy, a subclass of PSPACE. With arbitrary real coordinates, Euclidean TSP cannot be in such classes...
Click to read more »Polynomial identity testing
Selasa, 2026-03-31 08:31:10many other areas of computational complexity, such as the proof that IP=PSPACE. In addition, PIT has applications to Tutte matrices and also to primality...
Click to read more »Arthur–Merlin protocol
Rabu, 2026-05-27 06:30:41class AM[poly(n)] is equal to the class, IP, which is known to be equal to PSPACE and is widely believed to be stronger than the class AM[2]. MA is contained...
Click to read more »Formula game
Selasa, 2024-01-09 06:28:29strategy in the game represented by Φ {\displaystyle \Phi } . FORMULA-GAME is PSPACE-complete because it is exactly the same decision problem as True quantified...
Click to read more »Catalytic computing
Minggu, 2026-07-19 13:45:01and strengthening the case in the negative for the question of whether PSPACE=P. A related phenomenon to catalytic computing occurs in the study of space-efficient...
Click to read more »Probabilistic Turing machine
Minggu, 2026-01-18 10:38:26tricked by the all-powerful prover machine. For example, the class IP equals PSPACE, but if randomness is removed from the verifier, we are left with only NP...
Click to read more »Alternating Turing machine
Senin, 2026-06-22 22:31:45decidable in exponential time These are similar to the definitions of P, PSPACE, and EXPTIME, considering the resources used by an ATM rather than a deterministic...
Click to read more »Kinodynamic planning
Selasa, 2026-03-17 09:53:39deterministic methods. However, all motion planning methods are subject to the PSPACE-hardnesss of classical motion planning even without dynamics, which means...
Click to read more »Linear temporal logic
Selasa, 2026-05-05 23:40:51AG(EF(p)). Model checking and satisfiability against an LTL formula are PSPACE-complete problems. LTL synthesis and the problem of verification of games...
Click to read more »Computation tree logic
Rabu, 2026-03-04 06:22:17semantics. We label states. QCTL* = QCTL = MSO over graphs. Model checking is PSPACE-complete but satisfiability is undecidable. A reduction from the model-checking...
Click to read more »Type inhabitation
Senin, 2025-03-24 10:39:52that for simply typed lambda calculus the type inhabitation problem is PSPACE-complete. For other calculi, like System F, the problem is even undecidable...
Click to read more »NEXPTIME
Senin, 2026-05-18 18:37:50consider that when only one prover is present, we can only recognize all of PSPACE; the verifier's ability to "cross-examine" the two provers gives it great...
Click to read more »Games, Puzzles, and Computation
Sabtu, 2025-12-27 14:22:52computationally difficult: sudoku is NP-complete, Rush Hour and reversi are PSPACE-complete, and chess is EXPTIME-complete. Beyond proving new results along...
Click to read more »Metric interval temporal logic
Selasa, 2025-10-28 15:37:03over a signal is EXPSPACE-complete, while satisfiability for MITL0,∞ is PSPACE-complete. R. Alur, T. Feder, and T.A. Henzinger. The Benefits of Relaxing...
Click to read more »NSPACE
Sabtu, 2025-12-13 00:55:09= NSPACE(O(n)), where CSL is the class of context-sensitive languages. PSPACE = NPSPACE = ⋃ k ∈ N N S P A C E ( n k ) {\displaystyle \bigcup _{k\in \mathbb...
Click to read more »Quantum refereed game
Sabtu, 2026-08-08 07:23:4232nd AMC Symposium on Theory of Computing: 608–617. Watrous, J (2003). "PSPACE has constant-round quantum interactive proof systems". Theoretical Computer...
Click to read more »Richard Statman
Senin, 2025-12-15 12:21:02proof that the type inhabitation problem in simply typed lambda calculus is PSPACE-complete, lower bounds on simply typed lambda calculus, logical relations...
Click to read more »DSPACE
Senin, 2026-04-20 10:12:48function assumption in the space hierarchy theorem. L = DSPACE(O(log n)) PSPACE = ⋃ k ∈ N D S P A C E ( n k ) {\displaystyle \bigcup _{k\in \mathbb {N}...
Click to read more »List of NP-complete problems
Minggu, 2026-08-16 05:04:00of the reals § Complete problems Karp's 21 NP-complete problems List of PSPACE-complete problems Reduction (complexity) Grigoriev & Bodlaender (2007)....
Click to read more »Equivalence problem
Sabtu, 2023-04-15 00:41:47of finite-state automata, equivalence is decidable, and the problem is PSPACE-complete. Further, in the case of deterministic pushdown automata, equivalence...
Click to read more »DFA minimization
Senin, 2026-08-10 16:29:29there is no polynomial-time algorithm to minimize general NFAs unless P = PSPACE, an unsolved conjecture in computational complexity theory that is widely...
Click to read more »NL (complexity)
Minggu, 2025-09-21 02:56:51deterministic classes are known to be equal, so that for example we have PSPACE = NPSPACE. Arora, Sanjeev; Barak, Boaz (2009). Complexity Theory: A Modern...
Click to read more »Parallel computation thesis
Selasa, 2026-06-23 11:09:24polynomial number of processors are required for some PSPACE-complete problem, then it would show that PSPACE = P, a major unresolved hypothesis that is expected...
Click to read more »Implicit computational complexity
Senin, 2026-08-17 15:03:50complexity theory, a problem is assigned to a complexity class — such as P or PSPACE — by analysing the resource consumption (time, space) of a Turing machine...
Click to read more »Admissible rule
Jumat, 2026-04-10 13:15:37derivability problem (for rules or formulas) in these logics, which is PSPACE-complete. Admissibility in propositional logics is closely related to unification...
Click to read more »ACC0
Kamis, 2026-07-09 10:07:07results in complexity theory, including the time hierarchy theorem, IP = PSPACE, derandomization, and the representation of ACC0 via SYM+ circuits. Murray...
Click to read more »CTL*
Jumat, 2025-06-06 01:48:40model checking in CTL* is not worse than that of LTL: they both lie in PSPACE. The language of well-formed CTL* formulae is generated by the following...
Click to read more »Real RAM
Kamis, 2026-04-30 00:22:33real RAM unreasonable amounts of computational power, enabling it to solve PSPACE-complete problems in polynomial time. When analyzing algorithms for the...
Click to read more »Time hierarchy theorem
Kamis, 2026-01-01 12:02:16questions of computational complexity theory: whether P and NP, NP and PSPACE, PSPACE and EXPTIME, or EXPTIME and NEXPTIME are equal or not. The gap of approximately...
Click to read more »Oracle machine
Kamis, 2026-08-06 13:16:01Turing machines; for example, IPA≠PSPACEA for a random oracle A but IP = PSPACE. A machine with an oracle for the halting problem can determine whether...
Click to read more »Computer Othello
Kamis, 2026-08-20 02:46:24Computer Othello refers to computer architecture encompassing computer hardware and computer software capable of playing the game of Othello. A version...
Click to read more »Separation logic
Senin, 2026-04-06 04:34:20logic parameterized over the sorts of locations and data can be shown to be PSPACE-complete. An algorithm for solving this fragment in DPLL(T)-based SMT solvers...
Click to read more »Stanford Research Institute Problem Solver
Kamis, 2024-10-31 18:05:26Deciding whether any plan exists for a propositional STRIPS instance is PSPACE-complete. Various restrictions can be enforced in order to decide if a plan...
Click to read more »Metric temporal logic
Jumat, 2025-12-05 17:09:47\triangleright _{I}\neg \psi } . The satisfiability of ECL over signals is PSPACE-complete. A MTL-formula in positive normal form is defined almost as any...
Click to read more »Atomix (video game)
Kamis, 2026-05-07 01:53:07the problem of determining whether an Atomix puzzle has a solution is PSPACE-complete. Some heuristic approaches have been considered. Several open source...
Click to read more »Dynamic epistemic logic
Sabtu, 2026-06-13 09:49:50problem is solvable in polynomial time and its satisfiability problem is PSPACE-complete. Muddy children puzzle formalized with PAL: Here are some of the...
Click to read more »Victor Vianu
Sabtu, 2026-01-24 12:00:301991 Symposium on Theory of Computing) states that polynomial time equals PSPACE if and only if fixed-point logic equals partial fixed-point logic. At the...
Click to read more »Size-change termination principle
Minggu, 2023-08-13 17:19:01but a negative answer means "don't know". The decision problem for SCT is PSPACE-complete; however, there exists an algorithm that computes an approximation...
Click to read more »Novikov self-consistency principle
Minggu, 2026-08-16 09:27:35extended this result to show that the model could also be used to solve PSPACE problems in polynomial time. Deutsch shows that quantum computation with...
Click to read more »Nondeterministic finite automaton
Minggu, 2026-07-26 15:44:09from the initial state and check if some final state can be reached. It is PSPACE-complete to test, given an NFA, whether it is universal, i.e., if there...
Click to read more »2-EXPTIME
Kamis, 2026-07-02 02:22:27\mathbb {N} }{\mathsf {DTIME}}\left(2^{2^{n^{k}}}\right).} We know P ⊆ NP ⊆ PSPACE ⊆ EXPTIME ⊆ NEXPTIME ⊆ EXPSPACE ⊆ 2-EXPTIME ⊆ ELEMENTARY. 2-EXPTIME can...
Click to read more »S3 (programming language)
Senin, 2026-03-30 13:32:20entry point to the program, is reproduced here: GLOBAL STATIC (<STATUS 5;PSPACE 10001; TEMPLATE>) PROC KERMIT_THE_FROG IS ((<LIT "COMMAND">) REF()BYTE OPTION...
Click to read more »Transitive closure
Sabtu, 2026-07-25 17:28:24When transitive closure is added to second-order logic instead, we obtain PSPACE. Since the 1980s Oracle Database has implemented a proprietary SQL extension...
Click to read more »Log-space reduction
Minggu, 2025-12-28 20:43:18the case for showing that the true quantified Boolean formula problem is PSPACE-complete. This is because the need for memory in such reduction constructions...
Click to read more »Timed automaton
Rabu, 2026-08-19 21:20:55automaton and checking whether it accepts the empty language. This problem is PSPACE-complete. The universality problem of non-deterministic timed automaton...
Click to read more »Counting problem (complexity)
Selasa, 2026-07-28 02:16:59{\mathsf {P}}^{\#{\mathsf {P}}}={\mathsf {P}}^{\mathsf {PP}}\subset {\mathsf {PSPACE}}} Also, P H ⊂ P # P [ 1 ] {\displaystyle {\mathsf {PH}}\subset {\mathsf...
Click to read more »Online optimization
Rabu, 2026-08-05 03:32:26between the online and offline algorithms' performance. This problem is PSPACE-complete. Many formal problems offer more than one online algorithm as a...
Click to read more »Conjunctive query
Senin, 2025-12-01 09:48:58conjunctive queries and are thus at least as hard (in fact, relational algebra is PSPACE-complete with respect to combined complexity and is therefore even harder...
Click to read more »Computational hardness assumption
Selasa, 2026-07-07 01:06:11complexity class C {\displaystyle C} , in particular NP-hard (but often also PSPACE-hard, PPAD-hard, etc.). This means that they are at least as hard as any...
Click to read more »Outline of algorithms
Selasa, 2026-08-18 11:09:47method P (complexity) NP (complexity) NP-completeness NP-hardness EXPTIME PSPACE BPP (complexity) BQP Undecidable problem Halting problem Rice's theorem...
Click to read more »Richard Lipton
Selasa, 2026-05-12 12:37:49interactive proof systems Karloff-Nisan and Shamir, including the result IP = PSPACE. In the area of game theory, more specifically of non-cooperative games...
Click to read more »FIXP
Senin, 2026-06-15 10:01:11whereas FIXP is conjectured to be much harder, and lie in the "harder" end of PSPACE. Computing an approximate Nash equilibrium to any factor smaller than 1/2...
Click to read more »Rado graph
Sabtu, 2026-05-09 06:33:20sentence can be done more quickly than exponential time, as the problem is PSPACE-complete. The Rado graph is ultrahomogeneous, and thus is the Fraïssé limit...
Click to read more »Action description language
Kamis, 2026-07-23 23:11:58and thus ADL is strictly more brief than STRIPS. ADL planning is still a PSPACE-complete problem. Most of the algorithms polynomial space even if the preconditions...
Click to read more »Word equation
Rabu, 2026-07-01 16:54:49algorithm, showing that the solubility problem for word equations is in PSPACE. In 2006, Plandowski and Wojciech Rytter showed that minimal solutions of...
Click to read more »Finite model theory
Selasa, 2026-04-28 23:41:36determining whether a given sentence has probability tending to zero or to one is PSPACE-complete. A similar analysis has been performed for more expressive logics...
Click to read more »Modal μ-calculus
Senin, 2026-06-01 12:54:07checking, satisfiability and validity problems of linear modal μ-calculus are PSPACE-complete. Actually, the complexity of the satisfiability problem of graded...
Click to read more »Rod Downey
Kamis, 2026-03-19 04:37:45"Fixed-parameter tractability and completeness. IV. On completeness for W[P] and PSPACE analogues", Annals of Pure and Applied Logic, 73 (3): 235–276, doi:10...
Click to read more »Unambiguous finite automaton
Rabu, 2026-02-11 00:29:32It is indeed unambiguous as there exists only one nth last letter. Three PSPACE-hard problems for general NFA belong to PTIME for DFA and are now considered...
Click to read more »Serge Abiteboul
Minggu, 2026-08-16 06:41:21theory, the Abiteboul–Vianu Theorem states that polynomial time is equal to PSPACE if and only if fixed point logic is the same as partial fixed point logic...
Click to read more »HHL algorithm
Minggu, 2026-08-16 12:39:11poly-logarithmic runtime in κ {\displaystyle \kappa } would imply that BQP is equal to PSPACE, which is believed to be false. The dominant source of error is the application...
Click to read more »Succinct game
Jumat, 2026-08-14 02:42:28the value of such a game up to a multiplicative factor is known to be in PSPACE. Determining whether a pure Nash equilibrium exists is a Σ 2 P {\displaystyle...
Click to read more »Heyting algebra
Minggu, 2026-07-26 06:08:46the problem was established by Richard Statman in 1979, who showed it was PSPACE-complete and hence at least as hard as deciding equations of Boolean algebra...
Click to read more »Index of computing articles
Kamis, 2026-08-13 00:09:03Preprocessor – Primitive recursive function – Programming language – Prolog – PSPACE-complete – Pulse-code modulation (PCM) – Pushdown automaton – Python QuarkXPress...
Click to read more »Kosaburo Hashiguchi
Minggu, 2026-02-15 05:59:02smallest examples.[H88] A simpler method, showing also that the problem is PSPACE-complete, was provided in 2005 by Kirsten. Earlier, in 1979, Hashiguchi...
Click to read more »Low (complexity)
Senin, 2026-06-22 22:13:39polynomial-time algorithms, while retaining a polynomial overall running time. PSPACE (with restricted oracle access mechanism) is also self-low, and this can...
Click to read more »Security of cryptographic hash functions
Rabu, 2026-07-29 17:46:04of certain elements in this group. This is supposed to be hard, at least PSPACE-complete.[dubious – discuss] For this hash, an attack was eventually discovered...
Click to read more »2004 European Parliament election in the Czech Republic
Senin, 2026-06-22 22:03:04Retrieved 1 August 2016. Holpuch, Jan. "EU.ODS.cz / ODS a volby do EP". euods.pspace.cz. Archived from the original on 10 October 2007. Retrieved 15 March 2017...
Click to read more »Implicit graph
Jumat, 2025-03-21 00:41:07n)-bit bitstrings), SL (the analogous class for undirected graphs), and PSPACE (the class of problems that may be characterized by reachability in implicit...
Click to read more »Congestion game
Kamis, 2026-07-30 08:24:28implies that finding a Nash equilibrium reachable from a specified state is PSPACE-complete. For every problem in the complexity class PLS (essentially, every...
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