Thompson-like groups, Reidemeister numbers, and fixed points

We investigate fixed-point properties of automorphisms of groups similar to R. Thompson’s group $F$. Revisiting work of Gon\c{c}alves-Kochloukova, we deduce a cohomological criterion to detect infinite fixed-point sets in the abelianization, implying the so-called property $R_{\mathrm{\infty }}$. Using the BNS $\mathrm{\Sigma }$-invariant and drawing from works of Gon\c{c}alves-Sankaran-Strebel and Zaremsky, we show that our tool applies to many $F$-like groups, including Stein’s $F_{2,3}$, Cleary’s $F_{\tau }$, the Lodha-Moore groups, and the braided version of $F$.