Algebraic and Geometric Topology
We exhibit infinite families of embedded tori in 4–manifolds that are topologically isotopic but smoothly distinct. The interesting thing about these tori is that they are topologically trivial in the sense that each bounds a topologically embedded solid handlebody. This implies that there are stably ribbon surfaces in 4–manifolds that are not ribbon.
Sunukjian, Nathan and Hoffman, Neil R., "Null-homologous exotic surfaces in 4–manifolds" (2020). University Faculty Publications and Creative Works. 132.