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Dynamical Uniform Boundedness Conjecture


The dynamical uniform boundedness conjecture asserts a uniform bound for the number of preperiodic points of fixed-degree morphisms of projective space over number fields (Morton and Silverman 1994; Silverman 2007, p. 95). Fix integers d>=2, N>=1, and D>=1. There is a constant C=C(d,N,D) such that, for every number field K with extension field degree [K:Q]<=D and every morphism f:P^N->P^N of degree d defined over K,

 |PrePer(f,P^N(K))|<=C(d,N,D),

where PrePer(f,P^N(K)) is the set of preperiodic points in P^N(K).

Here d is the common total degree of the homogeneous polynomials giving f in homogeneous coordinates, with no common zero in projective space over an algebraic closure of K. The set of preperiodic points for each individual f over K is known to be finite. The conjecture asks for a bound that is independent of f and of the choice of K within the specified extension field degree bound (Silverman 2007, p. 95).


See also

Number Field, Preperiodic Point, Projective Space

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References

Morton, P. and Silverman, J. H. "Rational Periodic Points of Rational Functions." Int. Math. Res. Not. 1994, 97-110, 1994. https://doi.org/10.1155/S1073792894000127.Numberphile. "A Fascinating Thing about Fractions." Dec. 15, 2019. https://www.youtube.com/watch?v=N92w4e-hrA4.Silverman, J. H. The Arithmetic of Dynamical Systems. New York: Springer, 2007. https://doi.org/10.1007/978-0-387-69904-2.

Cite this as:

Weisstein, Eric W. "Dynamical Uniform Boundedness Conjecture." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/DynamicalUniformBoundednessConjecture.html

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