Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spatio-Temporal Analysis of Topic Popularity in Twitter   We present the first comprehensive characterization of the diffusion of ideas
on Twitter, studying more than 4000 topics that include both popular and less
popular topics. On a data set containing approximately 10 million users and a
comprehensive scraping of all the tweets posted by these users between June
2009 and August 2009 (approximately 200 million tweets), we perform a rigorous
temporal and spatial analysis, investigating the time-evolving properties of
the subgraphs formed by the users discussing each topic. We focus on two
different notions of the spatial: the network topology formed by
follower-following links on Twitter, and the geospatial location of the users.
We investigate the effect of initiators on the popularity of topics and find
that users with a high number of followers have a strong impact on popularity.
We deduce that topics become popular when disjoint clusters of users discussing
them begin to merge and form one giant component that grows to cover a
significant fraction of the network. Our geospatial analysis shows that highly
popular topics are those that cross regional boundaries aggressively.

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The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
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The categories of this paper are: q-fin
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The categories of this paper are: econ
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
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The categories of this paper are: atom-ph
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The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
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The categories of this paper are: eess
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The categories of this paper are: funct-an
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-th