Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optimal prediction and the Klein-Gordon equation   The method of optimal prediction is applied to calculate the future means of
solutions to the Klein-Gordon equation. It is shown that in an appropriate
probability space, the difference between the average of all solutions that
satisfy certain constraints at time t=0, and the average computed by an
approximate method, is small with high probability.

8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph