Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Martingale Transformations of Brownian Motion with Application to
  Functional Equations   We describe the classes of functions $f=(f(x), x\in R)$, for which processes
$f(W_t)-Ef(W_t)$ and $f(W_t)/Ef(W_t)$ are martingales. We apply these results
to give a martingale characterization of general solutions of the quadratic and
the D'Alembert functional equations. We study also the time-dependent
martingale transformations of a Brownian Motion.

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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-bio
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The categories of this paper are: supr-con
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The categories of this paper are: hep-ex
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The categories of this paper are: econ
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin
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The categories of this paper are: cond-mat
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The categories of this paper are: acc-phys
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The categories of this paper are: nlin
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The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: hep-lat