In this paper we
construct an action of a compact matrix quantum group on a Cuntz algebra or a
UHF-algebra, and investigate the fixed point subalgebra of the algebra under the
action. Especially we consider the action of μU(2) on the Cuntz algebra
𝒪2 and the action of SμU(2) on the UHF-algebra of type 2∞. We show
that these fixed point subalgebras are generated by a sequence of Jones’
projections.