Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $k\texttt{-experts}$ -- Online Policies and Fundamental Limits   We introduce the $\texttt{$k$-experts}$ problem - a generalization of the
classic Prediction with Expert's Advice framework. Unlike the classic version,
where the learner selects exactly one expert from a pool of $N$ experts at each
round, in this problem, the learner can select a subset of $k$ experts at each
round $(1\leq k\leq N)$. The reward obtained by the learner at each round is
assumed to be a function of the $k$ selected experts. The primary objective is
to design an online learning policy with a small regret. In this pursuit, we
propose $\texttt{SAGE}$ ($\textbf{Sa}$mpled Hed$\textbf{ge}$) - a framework for
designing efficient online learning policies by leveraging statistical sampling
techniques. For a wide class of reward functions, we show that $\texttt{SAGE}$
either achieves the first sublinear regret guarantee or improves upon the
existing ones. Furthermore, going beyond the notion of regret, we fully
characterize the mistake bounds achievable by online learning policies for
stable loss functions. We conclude the paper by establishing a tight regret
lower bound for a variant of the $\texttt{$k$-experts}$ problem and carrying
out experiments with standard datasets.

12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin