CONCERNING THE SPANS OF CERTAIN PLANE SEPARATING CONTINUA
T. T. West, Andrzej Lelek · 1999
Let X be a plane separating continuum. Suppose C is a convex space contained in a bounded component of R 2 X. It is shown that the span of the boundary of C is a lower bound for both the span and semispan of X. It is also shown that if a span of X is equal to the breadth of X and Y satises certain conditions relative to X then that span of X is an upper bound for the corresponding span of Y.