Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On automorphisms of flag spaces   We show that the automorphisms of the flag space associated with a
3-dimensional projective space can be characterized as bijections preserving a
certain binary relation on the set of flags in both directions. From this we
derive that there are no other automorphisms of the flag space than those
coming from collineations and dualities of the underlying projective space.
Further, for a commutative ground field, we discuss the corresponding flag
variety and characterize its group of automorphic collineations.

7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg