Camara and Krejci? ? k have studied properties of operators concerning with an antiunitary operator C (see 1). In this paper we show that if T = (T₁, , Tₙ) is a commuting n -tuple of Hilbert space operators and C is an antiunitary, then (CTC^-1) = (T) ^, where (T) is the Taylor spectrum of T, (T) ^ = \z = (z₁, , zₙ): z = (z₁, , zₙ) (T) \ and CTC^-1 = (CT₁C^-1, , CTₙC^-1). Also we will show ₓ (CTC^-1) = \z: z ₓ (T) \, where ₓ (T) is the Xia spectrum of T.
Chō et al. (Wed,) studied this question.