TY - JOUR AU - Qiang, Xiangqi PY - 2026 TI - Continuous orbit equivalence of groupoid actions JO - AIMS Mathematics SP - 13287 EP - 13303 VL - 11 IS - 5 AB - In this paper, I studied continuous actions of étale groupoids on compact Hausdorff spaces and the associated operator algebras. I introduced notions of conjugacy and continuous orbit equivalence for such groupoid actions and characterized them in terms of the corresponding transformation groupoids and their reduced C ∗ -algebras. In particular, I proved that two topologically free actions are continuously orbit equivalent if and only if their associated transformation groupoid C ∗ -algebras are isomorphic, and if and only if there exists a C ∗ -algebra isomorphism preserving the canonical Cartan subalgebras between the corresponding reduced C ∗ -algebras of these transformation groupoids. UR - https://doi.org/10.3934/math.2026548 DO - 10.3934/math.2026548