Abstract
For two languagesX and Y, the middle quotient of X with respect to Y is denoted by and defined as
and
. In addition, if
coincides with
where
and u is the reversal of v}, then
is a stable middle quotient, denoted by
. This paper proves that for every recursively enumerable language
and
, where A
B
C, and D are a linear language, a deterministic linear binary language, a linear language, and a minimal deterministic linear ternary language, respectively. Consequently
and
hold, too