Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A simple proof of the Fundamental Theorem of Calculus for the Lebesgue
  integral   This paper contains a new elementary proof of the Fundamental Theorem of
Calculus for the Lebesgue integral. The hardest part of our proof simply
concerns the convergence in ${\rm L}^1$ of a certain sequence of step
functions, and we prove it using only basic elements from Lebesgue integration
theory.

22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex