Clusters of submerged subharmonic isles with rare attractors in nonlinear machine dynamics

This work is devoted to new nonlinear effects in the machine dynamics. This article presents a new type of subharmonic solutions which in the bifurcation diagrams have the form of the isles, all solutions of which are unstable except for small ranges of the bifurcation parameter at the edges of the isles. It is shown that such isles can form clusters, which we assume are typical topological formation for a wide class of systems