ACTA MATHEMATICA HUNGARICA, vol.134, no.4, pp.565-570, 2012 (SCI-Expanded)
In [4], Csaszar has introduced the notions of weak structures and the structures alpha(w), pi(w), sigma(w), beta(w). The main aim of this paper is to introduce and study properties of the structures r(w), alpha(w), pi(w), sigma(w) and beta(w).