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  2. Unknotting problem - Wikipedia

    en.wikipedia.org/wiki/Unknotting_problem

    First steps toward determining the computational complexity were undertaken in proving that the problem is in larger complexity classes, which contain the class P. By using normal surfaces to describe the Seifert surfaces of a given knot, Hass, Lagarias & Pippenger (1999) showed that the unknotting problem is in the complexity class NP.

  3. Smale's problems - Wikipedia

    en.wikipedia.org/wiki/Smale's_problems

    Smale's problems is a list of eighteen unsolved problems in mathematics proposed by Steve Smale in 1998 [1] and republished in 1999. [2] Smale composed this list in reply to a request from Vladimir Arnold, then vice-president of the International Mathematical Union, who asked several mathematicians to propose a list of problems for the 21st century.

  4. Polynomial evaluation - Wikipedia

    en.wikipedia.org/wiki/Polynomial_evaluation

    This problem arises frequently in practice. In computational geometry, polynomials are used to compute function approximations using Taylor polynomials. In cryptography and hash tables, polynomials are used to compute k-independent hashing. In the former case, polynomials are evaluated using floating-point arithmetic, which is not exact. Thus ...

  5. Hilbert's seventeenth problem - Wikipedia

    en.wikipedia.org/wiki/Hilbert's_seventeenth_problem

    An n-variable instance of 3-SAT can be realized as a positivity problem on a polynomial with n variables and d=4. This proves that positivity testing is NP-Hard . More precisely, assuming the exponential time hypothesis to be true, v ( n , d ) = 2 Ω ( n ) {\displaystyle v(n,d)=2^{\Omega (n)}} .

  6. Existential theory of the reals - Wikipedia

    en.wikipedia.org/wiki/Existential_theory_of_the...

    That is, every problem in the existential theory of the reals has a polynomial-time many-one reduction to an instance of one of these problems, and in turn these problems are reducible to the existential theory of the reals. [4] [17] A number of problems of this type concern the recognition of intersection graphs of a certain type.

  7. Karp's 21 NP-complete problems - Wikipedia

    en.wikipedia.org/wiki/Karp's_21_NP-complete_problems

    In computational complexity theory, Karp's 21 NP-complete problems are a set of computational problems which are NP-complete.In his 1972 paper, "Reducibility Among Combinatorial Problems", [1] Richard Karp used Stephen Cook's 1971 theorem that the boolean satisfiability problem is NP-complete [2] (also called the Cook-Levin theorem) to show that there is a polynomial time many-one reduction ...

  8. P (complexity) - Wikipedia

    en.wikipedia.org/wiki/P_(complexity)

    The most difficult problems in P are P-complete problems. Another generalization of P is P/poly, or Nonuniform Polynomial-Time. If a problem is in P/poly, then it can be solved in deterministic polynomial time provided that an advice string is given that depends only on the length of the input. Unlike for NP, however, the polynomial-time ...

  9. Polynomial - Wikipedia

    en.wikipedia.org/wiki/Polynomial

    For example, they are used to form polynomial equations, which encode a wide range of problems, from elementary word problems to complicated scientific problems; they are used to define polynomial functions, which appear in settings ranging from basic chemistry and physics to economics and social science; and they are used in calculus and ...