Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On D.K. Biss' papers "The homotopy type of the matroid Grassmannian" and
  "Oriented matroids, complex manifolds, and a combinatorial model for BU"   We point out a flaw in papers by Daniel Biss devoted to homotopy type of
matroid Grassmannians.

20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
24
The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph