Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lognormal Distributions and Geometric Averages of Positive Definite
  Matrices   This article gives a formal definition of a lognormal family of probability
distributions on the set of symmetric positive definite (PD) matrices, seen as
a matrix-variate extension of the univariate lognormal family of distributions.
Two forms of this distribution are obtained as the large sample limiting
distribution via the central limit theorem of two types of geometric averages
of i.i.d. PD matrices: the log-Euclidean average and the canonical geometric
average. These averages correspond to two different geometries imposed on the
set of PD matrices. The limiting distributions of these averages are used to
provide large-sample confidence regions for the corresponding population means.
The methods are illustrated on a voxelwise analysis of diffusion tensor imaging
data, permitting a comparison between the various average types from the point
of view of their sampling variability.

17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th