For a continuous map on the unit interval or circle, we define the bifurcation set to be the collection of those interval holes whose surviving set is sensitive to arbitrarily small changes of (some of) their endpoints. By assuming a global perspective and focusing on the geometric and topological properties of this collection rather than the surviving sets of individual holes, we obtain a novel topological invariant for one-dimensional dynamics. We provide a detailed description of this invariant in the realm of transitive maps and observe that it carries fundamental dynamical information. In particular, for transitive non-minimal piecewise monotone maps, the bifurcation set encodes the topological entropy and strongly depends on the behavior of the critical points.
Fuhrmann, G., Gröger, M., & Passeggi, A. (2021). The bifurcation set as a topological invariant for one-dimensional dynamics. Nonlinearity, 34(3), Article 1366. https://doi.org/10.1088/1361-6544/abb78c