Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Group Discounts Compatible with Buyer Privacy   We show how group discounts can be offered without forcing buyers to
surrender their anonymity, as long as buyers can use their own computing
devices (e.g. smartphone, tablet or computer) to perform a purchase.
Specifically, we present a protocol for privacy-preserving group discounts. The
protocol allows a group of buyers to prove how many they are without disclosing
their identities. Coupled with an anonymous payment system, this makes group
discounts compatible with buyer privacy (that is, buyer anonymity).

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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: math-ph
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The categories of this paper are: stat
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The categories of this paper are: q-bio
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The categories of this paper are: funct-an
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The categories of this paper are: astro-ph
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The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom