Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Time-scale dependence of correlations among foreign currencies   For the purpose of elucidating the correlation among currencies, we analyze
daily and high-resolution data of foreign exchange rates. There is strong
correlation for pairs of currencies of geographically near countries. We show
that there is a time delay of order less than a minute between two currency
markets having a strong cross-correlation. The cross-correlation between
exchange rates is lower in shorter time scale in any case. As a corollary we
notice a kind of contradiction that the direct Yen-Dollar rate significantly
differs from the indirect Yen-Dollar rate through Euro in short time scales.
This result shows the existence of arbitrage opportunity among currency
exchange markets.

16
The categories of this paper are: stat
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn