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Computational complexity
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In Quantum Games, There’s No Way to Play the Odds
These games combine quantum entanglement, infinity and impossible-to-calculate winning probabilities. But if researchers can crack them, they’ll reveal deep mathematical secrets.
Major Quantum Computing Advance Made Obsolete by Teenager
18-year-old Ewin Tang has proven that classical computers can solve the “recommendation problem” nearly as fast as quantum computers. The result eliminates one of the best examples of quantum speedup.
A Short Guide to Hard Problems
What’s easy for a computer to do, and what’s almost impossible? Those questions form the core of computational complexity. We present a map of the landscape.
Finally, a Problem That Only Quantum Computers Will Ever Be Able to Solve
Computer scientists have been searching for years for a type of problem that a quantum computer can solve but that any possible future classical computer cannot. Now they’ve found one.
First Big Steps Toward Proving the Unique Games Conjecture
The latest in a new series of proofs brings theoretical computer scientists within striking distance of one of the great conjectures of their discipline.
One-Way Salesman Finds Fast Path Home
The real-world version of the famous “traveling salesman problem” finally gets a good-enough solution.
Subhash Khot, Playing Unique Games in Washington Square Park
The theoretical computer scientist behind the influential Unique Games Conjecture delights in the wonders of New York’s Washington Square Park, where he ponders the impossible.
Graph Isomorphism Vanquished — Again
Just five days after posting a retraction, László Babai announced that he had fixed the error in his landmark graph isomorphism algorithm.
Complexity Theory Problem Strikes Back
The legendary graph isomorphism problem may be harder than a 2015 result seemed to suggest.