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