Abstrakt
In the present article we provide an example of two closed non-sigma-lower porous sets of real numbers A, B such that the product A x B is lower porous. On the other hand, we prove the following: Let X and Y be topologically complete metric spaces, let A be a non-sigma-lower porous Suslin subset of X and let B be a non-sigma-porous Suslin subset of Y.
Then the product A x B is non-sigma-lower porous. We also provide a brief summary of some basic properties of lower porosity, including a simple characterization of Suslin non-sigma-lower porous sets in topologically complete metric spaces.