Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fourier Multipliers and Littlewood-Paley For Modulation Spaces   In this paper we have studied Fourier multipliers and Littlewood-Paley square
functions in the context of modulation spaces. We have also proved that any
bounded linear operator from modulation space $\mathcal{M}_{p,q}(\R^n), 1\leq
p,q\leq \infty,$ into itself possesses an $l_2-$valued extension. This is an
analogue of a well known result due to Marcinkiewicz and Zygmund on classical
$L^p-$spaces.

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The categories of this paper are: hep-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
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The categories of this paper are: acc-phys
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The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg
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The categories of this paper are: eess
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The categories of this paper are: physics
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The categories of this paper are: quant-ph
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The categories of this paper are: stat
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The categories of this paper are: nucl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int