The connected subsets of the usual real line are \b[the empty set and all <interval>[intervals]], including singletons, bounded <interval>[intervals] of any endpoint type, rays, and the whole line. Equivalently, a nonempty subset is connected exactly when it contains every point between any two of its points.

Solution

Past exam of the options II course of the University of Oxford / 2010 / E / E3 / a / ii / Solution

 Solution (source code)