thanks Ted gives a quick reply. I will see it you mentioned. 

Best Regards.

2016-03-08 23:26 GMT+08:00 Ted Yu <yuzhihong@gmail.com>:
This seems related:

the second paragraph under Implementation and theory

On Tue, Mar 8, 2016 at 4:49 AM, Minglei Zhang <mingleifly@gmail.com> wrote:
hello, experts.

    I am a student. and recently, I read a paper about Actor Model of Computation:Scalable Robust Information System. In the paper I am trying to understand it's concept. But with the following sentence makes me confusing.

# Messages are the unit of communication 1

Reference to 1

All physically computable functions can be implemented using the lambda calculus. It is a consequence of the Actor Model that there are some computations that cannot be implemented in the lambda calculus

My question, What are there computations that cannot be implemented in Lambda calculus ? 

thanks.
Minglei.