Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the non-Paschian ordered planes   We give a non-Paschian plane based on the property of betweenness which
cannot be derived from an ordering of the points of a line. In this model there
is no possibility to define the congruence of segments but we can define angle,
triangle and angle measure, respectively. With respect to our definitions the
plane has an elliptic character, meaning that the sum of the angles of a
triangle is greater than $\pi$.

12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph