d-calibers and d-tightness in compact spaces

We study the Čech-Stone compactification of the space Seq(u). We show that its remainder is Fσκ-closed whenever u is a P(κ)-point and b⩾κ>ω. Our results enable us to solve a recent problem by Okunev and Tkachuk regarding a possible relationship between d-tightness and d-calibers in compact spaces.