Sierpinski-Zygmund functions that have the Cantor intermediate value property

by

Krzysztof Banaszewski and Tomasz Natkaniec

7 pages

We construct (in ZFC) an example of Sierpinski-Zygmund function having the Cantor intermediate value property CIVP and observe that every such function does not have the strong Cantor intermediate value property SCIVP, which solves a problem of R. Gibson. Moreover we prove that both families: SCIVP functions and CIVP\setminus SCIVP functions are 2c dense in the uniform closure of the class of CIVP functions. We show also that if the real line is not a union of less than continuum many its meager subsets, then there exists an almost continuous Sierpinski-Zygmund function having the Cantor intermediate value property. Because such a function does not have the strong Cantor intermediate value property, it is not extendable. This solves another problem of Gibson.


LaTeX 2.09 source file.

DVI, TEX and Postscript files are available at the Topology Atlas preprints side.

Last modified August 9, 1997.