Zoom, Online seminar
(線上演講 Zoom)
Uniform Approximation Problems of Expanding Markov Map
Yubin He (South China University of Technology)
Abstract
Let
![](https://chart.googleapis.com/chart?cht=tx&chl=%24T%24&chf=bg,s,333333&chco=ffffff)
be an expanding Markov map of the interval
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%5B0%2C1%5D%24&chf=bg,s,333333&chco=ffffff)
with a finite partition. Let
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%5Cmu_%7B%5Cphi%7D%24&chf=bg,s,333333&chco=ffffff)
be an invariant Gibbs measure associated with a Hölder continuous potential
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%5Cphi%24&chf=bg,s,333333&chco=ffffff)
. In this talk, we investigate the size of the uniform approximation set
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%24%5Cmathcal%7BU%7D%5E%7B%5Ckappa%7D(x)%3A%3D%5C%7By%20%5Cin%20%5B0%2C%201%5D%3A%20%5Cforall%20N%20%5Cgg%201%2C~%5Cexists%20n%20%5Cleq%20N%2C%20%5Ctext%7B%20such%20that%20%7D%20%7CT%5En%20x%20-%20y%7C%20%3C%20N%5E%7B-%5Ckappa%7D%5C%7D%2C%24%24&chf=bg,s,333333&chco=ffffff)
where
![](https://chart.googleapis.com/chart?cht=tx&chl=%20%24%5Ckappa%20%3E%200%24&chf=bg,s,333333&chco=ffffff)
and
![](https://chart.googleapis.com/chart?cht=tx&chl=%20%24x%20%5Cin%20%5B0%2C%201%5D%24&chf=bg,s,333333&chco=ffffff)
. The critical value of
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%5Ckappa%24&chf=bg,s,333333&chco=ffffff)
such that
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%5Cdim_H%20%5Cmathcal%7BU%7D%5E%7B%5Ckappa%7D(x)%20%3D%201%24&chf=bg,s,333333&chco=ffffff)
for
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%5Cmu_%7B%5Cphi%7D%24-a.e.~%24x%24&chf=bg,s,333333&chco=ffffff)
is proven to be
![](https://chart.googleapis.com/chart?cht=tx&chl=%241%2F%5Calpha_%7B%5Cmax%7D%24&chf=bg,s,333333&chco=ffffff)
, where
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%5Calpha_%7B%5Cmax%7D%20%3D%20%5Cint%20-%5Cphi%20d%5Cmu_%7B%5Cmax%7D%20%2F%20%5Cint%20%5Clog%20%7CT'%7C%20d%20%5Cmu_%7B%5Cmax%7D%24&chf=bg,s,333333&chco=ffffff)
and
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%5Cmu_%7B%5Cmax%7D%24%20&chf=bg,s,333333&chco=ffffff)
is the Gibbs measure associated with the potential
![](https://chart.googleapis.com/chart?cht=tx&chl=%24-%5Clog%20%7CT'%7C%24&chf=bg,s,333333&chco=ffffff)
. Moreover, when
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%5Ckappa%24%20&chf=bg,s,333333&chco=ffffff)
>1/
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%5Calpha_%7B%5Cmax%7D%24&chf=bg,s,333333&chco=ffffff)
, we show that for
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%5Cmu_%7B%5Cphi%7D%24&chf=bg,s,333333&chco=ffffff)
-a.e.~
![](https://chart.googleapis.com/chart?cht=tx&chl=%24x%24&chf=bg,s,333333&chco=ffffff)
, the Hausdorff dimension of
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%5Cmathcal%7BU%7D%5E%7B%5Ckappa%7D(x)%24%20&chf=bg,s,333333&chco=ffffff)
agrees with the multifractal spectrum of
![](https://chart.googleapis.com/chart?cht=tx&chl=%24%5Cmu_%7B%5Cphi%7D%24&chf=bg,s,333333&chco=ffffff)
.
Meeting Link
https://us02web.zoom.us/j/82058526043?pwd=Z0QzVXZVNDRTRkhJMG4rQ0dlSlkzUT09