3-sphere two 3-balls. This construction is analogous to a construction of a 2-sphere, performed by gluing the boundaries of a pair of disks. A disk is a 2-ball, and the boundary of a disk is a circle (a 1-sphere). Let a pair of disks be of the same diameter. Superpose them and glue corresponding points on their boundaries. Again one may think of the third dimension as temperature. Likewise, we may inflate the 2-sphere, moving the pair of disks to become the northern and southern hemispheres. After removing a single point from the 2-sphere, what remains is homeomorphic to the Euclidean
Public sphere that are "parallel discursive arenas where members of subordinated social groups invent and circulate counterdiscourses to formulate oppositional interpretations of their identities, interests, and needs". Benhabib notes that in Habermas' idea of the public sphere, the distinction between public and private issues separates issues that normally affect women (issues of "reproduction, nurture and care for the young, the sick, and the elderly") into the private realm and out of the discussion in the public sphere. She argues that if the public sphere is to be open to any discussion that affects the population, there cannot be distinctions between "what is"