Some similarity between contractions and Kannan mappings. Kikkawa, Misako; Suzuki, Tomonari — 2008 Fixed Point Theory and Applications [electronic only]
Only 3-generalized metric spaces have a compatible symmetric topology Tomonari Suzuki; Badriah Alamri; Misako Kikkawa — 2015 Open Mathematics We prove that every 3-generalized metric space is metrizable. We also show that for any ʋ with ʋ ≥ 4, not every ʋ-generalized metric space has a compatible symmetric topology.