Conceptual

Absorber Characterization of Subcontinua with Connected Boundaries

For a pi-n-Euclidean unicoherent Peano continuum with n at least 2, the proper subcontinua with connected boundary form exactly the pseudo-interior of the Hilbert cube C(X), proved by recognizing the complement as an F-sigma-absorber; the separating members form a D_2(F-sigma)-absorber.