Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On characterizations of learnability with computable learners   We study computable PAC (CPAC) learning as introduced by Agarwal et al.
(2020). First, we consider the main open question of finding characterizations
of proper and improper CPAC learning. We give a characterization of a closely
related notion of strong CPAC learning, and we provide a negative answer to the
open problem posed by Agarwal et al. (2021) whether all decidable PAC learnable
classes are improperly CPAC learnable. Second, we consider undecidability of
(computable) PAC learnability. We give a simple and general argument to exhibit
such undecidability, and we initiate a study of the arithmetical complexity of
learnability. We briefly discuss the relation to the undecidability result of
Ben-David et al. (2019), that motivated the work of Agarwal et al.

36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat