Completeness of fuzzy quasi-pseudometric spaces

Completeness of fuzzy quasi-pseudometric spaces

The purpose of this paper is to present the relations among the completeness of sequences, of filters and of nets in the framework of fuzzy quasi-pseudometric spaces. In particular, we show that right completeness of filters and of sequences are equivalent under special conditions of fuzzy quasi-pseudometrics. By introducing a kind of more general right K-Cauchy nets in fuzzy quasi-pseudometric spaces, the equivalence between the completeness of the nets and the sequential completeness is established.

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  • [1] E. Alemany and S. Romaguera, On right K-sequentially complete quasi-metric spaces, Acta Math. Hungar. 75, 267–278, 1997.
  • [2] N.F. Al-Mayahi and I.H. Radhi, The closure in fuzzy metric (normed) space, Tikrit J. Pure Sci. 18, 411–412, 2013.
  • [3] F. Castro-Company, S. Romaguera and P. Tirado, The bicompletion of fuzzy quasi- metric spaces, Fuzzy Sets Syst. 166, 56–64, 2011.
  • [4] Ş. Cobzaş, Completeness in quasi-pseudometric spaces–a survey, Math. 8, 1279, 2020.
  • [5] A.S. Davis, Indexed systems of neighbourhoods for general topological spaces, Amer. Math. Mon. 68, 886–893, 1961.
  • [6] D. Doitchinov, On completeness in quasi-metric spaces, Topology Appl. 30, 127–148, 1988.
  • [7] A. George and P. Veeramani, On some results in fuzzy metric spaces, Fuzzy Sets Syst. 64, 395–399, 1994.
  • [8] A. George and P. Veeramani, Some theorems in fuzzy metric spaces, J. Fuzzy Math. 3, 933–940, 1995.
  • [9] V. Gregori and J. Ferrer, A note on R. Stoltenberg’s completion theory of quasi- uniform spaces. Proc. Lond. Math. Soc. 49, 36–36, 1984.
  • [10] V. Gregori, A. López-Crevillén, S. Morillas and A. Sapena, On convergence in fuzzy metric spaces, Topology Appl. 156, 3002–3006, 2009.
  • [11] V. Gregori, J.J. Miñana, S. Morillas and A. Sapena, Characterizing a class of com- pletable fuzzy metric spaces, Topology Appl. 203, 3–11, 2016.
  • [12] V. Gregori, S. Morillas and A. Sapena, On completion of fuzzy quasi-metric spaces, Topology Appl. 153, 886–899, 2005.
  • [13] V. Gregori and S. Romaguera, Some properties of fuzzy metric spaces, Fuzzy Sets Syst. 115, 485–489, 2000.
  • [14] V. Gregori and S. Romaguera, On completion of fuzzy metric spaces, Fuzzy Sets Syst. 130, 399–404, 2002.
  • [15] V. Gregori and S. Romaguera, Fuzzy quasi-metric spaces, Appl. Gen. Topology 5, 129–136, 2004.
  • [16] V. Gregori, S. Romaguera and A. Sapena, A characterization of bicpmpletable fuzzy quasi-metric spaces, Fuzzy Sets Syst. 152, 395–402, 2005.
  • [17] J.C. Kelly, Bitopological spaces, Proc. Lond. Math. Soc. 12, 71–89, 1963.
  • [18] E.P. Klement, R. Mesiar and E. Pap, Triangular Norms, Kluwer Academic Publishers, Dordrecht, 2000.
  • [19] I. Kramosil and J. Michálek, Fuzzy metric and statistical metric spaces, Kybernetica 11, 326–334, 1975.
  • [20] K. Menger, Statistical metrics, Proc. Nat. Acad. Sci. USA. 28, 535–537, 1942.
  • [21] I.L. Reilly, A generalized contraction principle, Bull. Austral. Math. Soc. 10, 359–363, 1974.
  • [22] I.L. Reilly, I.L. Subrahmanyam and M.K. Vamanamurthy, Cauchy sequences in quasi- pseudo-metric spaces, Monatsh. Math. 93, 127–140, 1982.
  • [23] S. Romaguera, Left K-completeness in quasi-metric spaces, Math. Nachr. 157, 15–23, 1992.
  • [24] B. Schweizer and A. Sklar, Probabilistic metric spaces, North-Holland series in prob- ability and applied mathematics, Elsevier Science Publishing Co. Inc. 1983.
  • [25] H. Sherwood, On the completion of probabilistic metric spaces, Z. Wahrsch. Verw. Geb. 6, 62–64, 1966.
  • [26] R.A. Stoltenberg, Some properties of quasi-uniform spaces, Proc. Lond. Math. Soc. 17, 226–240, 1967.
  • [27] P.V. Subrahmanyam, Remarks on some fixed-point theorems related to Banach’s con- traction principle, J. Math. Phys. Sci. 8, 455–457, 1974.
  • [28] A. Wald, On a statistical generalization of metric spaces, Proc. Nat. Acad. Sci. USA. 29, 196–197, 1943.
  • [29] W.A. Wilson, On quasi-metric spaces, Amer. J. Math. 53, 675–684, 1931.
  • [30] J.R. Wu, X. Tang, Caristi’s fixed point theorem, Ekeland’s variational principle and Takahashi’s maximization theorem in fuzzy quasi-metric spaces, Topology Appl. 302, 108701, 2021.
  • [31] H. Yang and B. Pang, Fuzzy points based betweenness relations in L-convex spaces, Filomat 35 (10), 3521–3532, 2021.
  • [32] Y. Yue and J. Fang, Completeness in probabilistic quasi-uniform spaces, Fuzzy Sets and Systems 370, 34–62, 2019.
  • [33] L. Zhang and B. Pang, The category of residuated lattice valued filter spaces, Quaest. Math. https://doi.org/10.2989/16073606.2021.1973140, 2021.
  • [34] L. Zhang and B. Pang, Monoidal closedness of the category of $\top$-semiuniform conver- gence spaces, Hacet. J. Math. Stat. 51 (5), 1348–1370, 2022.
  • [35] F. Zhao and B. Pang, Equivalence among L-closure (interior) operators, L-closure (interior) systems and L-enclosed (internal) relations, Filomat 36 (3), 979–1003, 2022.