Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exact controllability in minimal time of the Navier-Stokes periodic flow
  in a 2D-channel   This work is concerned with the necessary conditions of optimality for a
minimal time control problem $(P)$ for the linearized Navier-Stokes periodic
flow in a 2D-channel, subject to a boundary input which acts on the transversal
component of the velocity. The objective in this problem is the reaching of the
laminar regime in a minimum time, as well as its preservation after this time.
The determination of the necessary conditions of optimality relies on the
analysis of intermediate minimal time control problems $(P_{k})$ for the
Fourier modes $"k"$ associated to the Navier-Stokes equations and on the proof
of the maximum principle for them. Also it is found that one can construct, on
the basis of the optimal controllers of problems $(P_{k}),$ a small time called
here \textit{quasi minimal} and a boundary controller which realizes the
required objective in $% (P).$

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The categories of this paper are: dg-ga
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The categories of this paper are: hep-th
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The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin