Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tightness of stationary distributions of a flexible-server system in the
  Halfin-Whitt asymptotic regime   We consider a large-scale flexible service system with two large server pools
and two types of customers. Servers in pool 1 can only serve type 1 customers,
while server in pool 2 are flexible -- they can serve both types 1 and 2. (This
is a so-called "N-system." Our results hold for a more general class of systems
as well.) The service rate of a customer depends both on its type and the pool
where it is served. We study a priority service discipline, where type 2 has
priority in pool 2, and type 1 prefers pool 1. We consider the Halfin-Whitt
asymptotic regime, where the arrival rate of customers and the number of
servers in each pool increase to infinity in proportion to a scaling parameter
$n$, while the overall system capacity exceeds its load by $O(\sqrt{n})$.
  For this system we prove tightness of diffusion-scaled stationary
distributions. Our approach relies on a single common Lyapunov function
$G^{(n)}(x)$, depending on parameter $n$ and defined on the entire state space
as a functional of the {\em drift-based fluid limits} (DFL). Specifically,
$G^{(n)}(x)=\int_0^\infty g(y^{(n)}(t)) dt$, where $y^{(n)}(\cdot)$ is the DFL
starting at $x$, and $g(\cdot)$ is a "distance" to the origin. ($g(\cdot)$ is
same for all $n$). The key part of the analysis is the study of the (first and
second) derivatives of the DFLs and function $G^{(n)}(x)$. The approach, as
well as many parts of the analysis, are quite generic and may be of independent
interest.

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The categories of this paper are: gr-qc
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The categories of this paper are: hep-ph
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The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
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The categories of this paper are: physics
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The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
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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: q-alg
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The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: cond-mat
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The categories of this paper are: econ
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The categories of this paper are: dg-ga