On some classes of expansions of ideals in $MV$-algebras

In this paper, we introduce the notions of expansion of ideals in $MV$-algebras, $ (tau,sigma)- $primary, $ (tau,sigma)$-obstinate  and $ (tau,sigma)$-Boolean  in $ MV- $algebras. We investigate the relations of them. For example, we show that every $ (tau,sigma)$-obstinate ideal of an $ MV-$ algebra is $ (tau,sigma)$-primary  and $ (tau,sigma)$-Boolean. In particular, we define an expansion $ sigma_{y} $ of ideals in an $ MV-$algebra. A characterization of expansion ideal with respect to $ sigma_{y} $ is given. Finally, we show that the class $ C(sigma_{y}) $ of all constant ideals relative to $ sigma_{y} $ is a Heyting algebra.