ABSTRACT
Learnability of languages is a challenging problem
in the domain of formal language identification. It is
known that the efficiency of a learning technique can
be measured by the size of some good samples (representative
or distinctive samples) formally called a
characteristic set. Our research focuses on the characteristic
set of k-acceptable languages. We proposed
a Gold-style learning algorithm called KRPNI which
applied the grammatical inference technique to identify
a language and expressed it by a k-DFA. In this
paper, we study the existence of such characteristic
sets. Our theoretical results show that there exists a
polynomial characteristic set for a k-acceptable language.
It is found that the size of the characteristic
set depends on the value of k, instead of the size of
an alphabet.