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COUNTABILITY AND APPROACH THEORY

  • Received : 2014.07.09
  • Accepted : 2014.10.06
  • Published : 2014.11.15

Abstract

In approach theory, we can provide arbitrary products of ${\infty}p$-metric spaces with a natural structure, whereas, classically only if we rely on a countable product and the question arises, then, whether properties which are derived from countability properties in metric spaces, such as sequential and countable compactness, can also do away with countability. The classical results which simplify the study of compactness in pseudometric spaces, which proves that all three of the main kinds of compactness are identical, suggest a further study of the category $pMET^{\infty}$.

Keywords

References

  1. J. Adamek, H. Herrlich, and G. E. Strecker, Abstract and concrete categories, Pure and Applied Mathematics, A Wiley-Interscience Series of Texts, Mono-graphs, and Tracts, New York, ISBN 0-471-60922-6, MR1051419 (91h:18001) 1990
  2. R. Baekeland and R. Lowen, Measures of Lindelof and separability in approach spaces, Internat. J. Math. And Math. Sci. vol. 173 (1994), 597-606.
  3. R. Baekeland and R. Lowen, Measures of compactness in approach spaces, Comm. Math. Univ. Carolinae, vol. 36 (1995), 327-345.
  4. G. Choquet, Convergences, Ann. Univ. Grenoble, Sect. Math. Phys. vol. 23 (1948), 57-112.
  5. D. Dikrajan and W. Tholen, Cathegorical Structure of Closure Operators, Mathematics and its Applications, Kluwer Academic Publishers MR1368854 (97i:18004), 1995.
  6. S. P. Franklin, Spaces in which sequences suffice, Fund. Math. 57 (1965), 107-115. https://doi.org/10.4064/fm-57-1-107-115
  7. S. P. Franklin, Spaces in which sequences suffice II, Fund. Math. 61 (1967), 51-56. https://doi.org/10.4064/fm-61-1-51-56
  8. R. Lowen, Kuratowski's measure of non-compactness revisited, Quart. J. Math. Oxford 2 (1988), 235-254.
  9. R. Lowen, Approach Spaces. A common supercategory of TOP and MET, Math. Nachr. 141 (1995), 183-226.
  10. R. Lowen, Approach Spaces. The missing link in the Topology-Uniformity- Metric triad, Oxford Science Publications, 1995.
  11. R. Lowen and C. Verbeeck, Local compactness in approach spaces I, Internat. J. Math. & Math. Sci. 21 (1998), no. 3, 429-438. https://doi.org/10.1155/S016117129800060X
  12. R. Lowen and B. Windels, On the quantification of uniform properties, Comment. Math. Univ. Carolinae 384 (1997), 749-759.
  13. R. Lowen and B. Windels, A-Unif: a common supercategory of UNIF and MET, Internat. J. Math. Sci. 21 (1998), 1-18. https://doi.org/10.1155/S0161171298000015
  14. S. A. Naimpally and B. D. Warrack, Proximity Spaces, Cambridge University Press, MR0278261 (43:3992) 1970.
  15. G. Preuss, Theory of Topological Structures, Mathematics and its Applications, Kluwer Academic Publishers MR0937052 (89m:54014) 1998.

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  1. SOME PROPERTIES OF CLOSURE-SEQUENTIAL APPROACH SPACES vol.33, pp.4, 2020, https://doi.org/10.14403/jcms.2020.33.4.405