Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lacunary matrices   We study unconditional subsequences of the canonical basis e_rc of elementary
matrices in the Schatten class S^p. They form the matrix counterpart to Rudin's
Lambda(p) sets of integers in Fourier analysis. In the case of p an even
integer, we find a sufficient condition in terms of trails on a bipartite
graph. We also establish an optimal density condition and present a random
construction of bipartite graphs. As a byproduct, we get a new proof for a
theorem of Erdos on circuits in graphs.

7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol