On zeta_1 zeta_2-semi pre open sets and zeta_1 zeta_2—quasi open sets

摘要

zeta_1 zeta_2-semi pre open sets are characterized by conditions. Condition under which a zeta_1 zeta_2-semi pre open set becomes a zeta_1 zeta_2- semi open set is given. Also we define zeta_1 zeta_2-quasi open sets in a biological space (X, zeta_1zeta_2) and discuss their properties.The concept of a semi pre-open set in a unital topological space was introduced by Andnjevic in the year 1986. A study of semi pre-open set in bitopological spaces was made by Khedr et al in the year 1992.