General Topology and Bi-Topology, Fuzzy Topology and Fuzzy Bi-Topology, Fuzzy Filters, Fuzzy Category and Fuzzy Set Theory.
Main publications:
W. Gahler, A. S. Abd-Allah and A. Kandil, “On extended fuzzy topologies”, Fuzzy Sets and Systems, 109 (2000), 149 - 172
A. Kandil, A. S. Abd-Allah and A. A. Nouh, “Operations and its applications on L-fuzzy bitopological spaces: Part I”, Fuzzy Sets and Systems, 106 (1999), 255 - 274
A. S. Abd-Allah, “General notions related to fuzzy filters”, The Journal of Fuzzy Mathematics, 10:2 (2002), 321 - 358
A. S. Abd-Allah, “Separation Axioms in Characterized Fuzzy Spaces.”, The Journal of Fuzzy Mathematics, 15:2 (2007), 291 - 329
A. S. Abd-Allah, A. Al-Khedhairi, “Characterized Fuzzy R2.5 and Characterized Fuzzy T3.5 Spaces.”, Journal of Advances in Mathematics, 13:1 (2017), 7048 - 7074