Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Memory effects on epidemic evolution: The susceptible-infected-recovered
  epidemic model   Memory has a great impact on the evolution of every process related to human
societies. Among them, the evolution of an epidemic is directly related to the
individuals' experiences. Indeed, any real epidemic process is clearly
sustained by a non-Markovian dynamics: memory effects play an essential role in
the spreading of diseases. Including memory effects in the
susceptible-infected-recovered (SIR) epidemic model seems very appropriate for
such an investigation. Thus, the memory prone SIR model dynamics is
investigated using fractional derivatives. The decay of long-range memory,
taken as a power-law function, is directly controlled by the order of the
fractional derivatives in the corresponding nonlinear fractional differential
evolution equations. Here we assume "fully mixed" approximation and show that
the epidemic threshold is shifted to higher values than those for the
memoryless system, depending on this memory "length" decay exponent. We also
consider the SIR model on structured networks and study the effect of topology
on threshold points in a non- Markovian dynamics. Furthermore, the lack of
access to the precise information about the initial conditions or the past
events plays a very relevant role in the correct estimation or prediction of
the epidemic evolution. Such a "constraint" is analyzed and discussed.

12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg