Tukey order among $F_{\sigma }$ ideals

Jialiang He, Michael Hrušák, Diego Rojas-Rebolledo +1

We investigate the Tukey order in the class of $F_{\sigma }$ ideals of subsets of $\omega$. We show that no nontrivial $F_{\sigma }$ ideal is Tukey below a $G_{\delta }$ ideal of compact sets. We introduce the…