On Topologies Generated by Lower Porosity

In the paper we study properties of a lower porosity of a set in a normed space (X, parallel to parallel to). Two topologies (p) under bar (X, parallel to parallel to) and (s) under bar (X, parallel to parallel to) on X generated by the lower porosity are defined. Relationships between these topologies and, previously defined by V. Kelar and L. Zajicek, topologies p(X, parallel to parallel to) and s(X, parallel to parallel to) are studied. Applying topologies (p) under bar (X, parallel to parallel to) and (s) under bar (X, parallel to parallel to) we characterize maximal additive class of lower porouscontinuous functions. Some relevant properties of defined topologies are considered.