638 research outputs found
Baker's conjecture for functions with real zeros
Baker's conjecture states that a transcendental entire functions of order less than 1/2 has no unbounded Fatou components. It is known that, for such functions, there are no unbounded periodic Fatou components and so it remains to show that they can also have no unbounded wandering domains. Here we introduce completely new techniques to show that the conjecture holds in the case that the transcendental entire function is real with only real zeros, and we prove the much stronger result that such a function has no orbits consisting of unbounded wandering domains whenever the order is less than 1. This raises the question as to whether such wandering domains can exist for any transcendental entire function with order less than 1.
Key ingredients of our proofs are new results in classical complex analysis with wider applications. These new results concern: the winding properties of the images of certain curves proved using extremal length arguments, growth estimates for entire functions, and the distribution of the zeros of entire functions of order less than 1
Permutable entire functions and multiply connected wandering domains
Let f and g be permutable transcendental entire functions. We use a recent analysis of the dynamical behaviour in multiply connected wandering domains to make progress on the long standing conjecture that the Julia sets of f and g are equal; in particular, we show that J(f)=J(g) provided that neither f nor g has a simply connected wandering domain in the fast escaping set
Multiply connected wandering domains of entire functions
The dynamical behaviour of a transcendental entire function in any periodic
component of the Fatou set is well understood. Here we study the dynamical
behaviour of a transcendental entire function in any multiply connected
wandering domain of . By introducing a certain positive harmonic
function in , related to harmonic measure, we are able to give the first
detailed description of this dynamical behaviour. Using this new technique, we
show that, for sufficiently large , the image domains contain
large annuli, , and that the union of these annuli acts as an absorbing
set for the iterates of in . Moreover, behaves like a monomial
within each of these annuli and the orbits of points in settle in the long
term at particular `levels' within the annuli, determined by the function .
We also discuss the proximity of and for large
, and the connectivity properties of the components of . These properties are deduced from new results about the behaviour
of an entire function which omits certain values in an annulus
Dynamics of meromorphic functions with direct or logarithmic singularities
We show that if a meromorphic function has a direct singularity over
infinity, then the escaping set has an unbounded component and the intersection
of the escaping set with the Julia set contains continua. This intersection has
an unbounded component if and only if the function has no Baker wandering
domains. We also give estimates of the Hausdorff dimension and the upper box
dimension of the Julia set of a meromorphic function with a logarithmic
singularity over infinity. The above theorems are deduced from more general
results concerning functions which have "direct or logarithmic tracts", but
which need not be meromorphic in the plane. These results are obtained by using
a generalization of Wiman-Valiron theory. The method is also applied to complex
differential equations.Comment: 29 pages, 2 figures; v2: some overall revision, with comments and
references added; to appear in Proc. London Math. So
Connectedness properties of the set where the iterates of an entire function are unbounded
We investigate the connectedness properties of the set I+(f) of points where the iterates of an entire function f are unbounded. In particular, we show that I+(f) is connected whenever iterates of the minimum modulus of f tend to ∞. For a general transcendental entire function f, we show that I+(f)∪ \{\infty\} is always connected and that, if I+(f) is disconnected, then it has uncountably many components, infinitely many of which are unbounded
Functions of small growth with no unbounded Fatou components
We prove a form of the theorem which gives strong estimates
for the minimum modulus of a transcendental entire function of order zero. We
also prove a generalisation of a result of Hinkkanen that gives a sufficient
condition for a transcendental entire function to have no unbounded Fatou
components. These two results enable us to show that there is a large class of
entire functions of order zero which have no unbounded Fatou components. On the
other hand we give examples which show that there are in fact functions of
order zero which not only fail to satisfy Hinkkanen's condition but also fail
to satisfy our more general condition. We also give a new regularity condition
that is sufficient to ensure that a transcendental entire function of order
less than 1/2 has no unbounded Fatou components. Finally, we observe that all
the conditions given here which guarantee that a transcendental entire function
has no unbounded Fatou components, also guarantee that the escaping set is
connected, thus answering a question of Eremenko for such functions
Correlation Between Handgrip Strength and Functional Fitness Among Older Adults
Please refer to the pdf version of the abstract located adjacent to the title
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