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c-compactness in locally compact groups and paratopological groups

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Abstract

We study c-compactness in two cases. First, we obtain some subclasses of locally compact groups where compactness and c-compactness coincide, and besides, a result due to Dikranjan and Uspenskij is generalized. We introduce c-compactness and h-completeness in the wider class of Hausforff paratopological groups. It is proved that the closure of any subgroup of a c-compact paratopological group is again a subgroup. We present an example of a non-compact h-complete paratopological group.

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References

  1. Arhangel’skii A. V., Reznichenko E.: Paratopological and semitopological groups versus topological groups. Topol. Appl. 151, 107–119 (2005)

    Article  MathSciNet  MATH  Google Scholar 

  2. A. V. Arhangel’skii and M. G. Tkachenko, Topological Groups and Related Structures, Atlantis Series in Mathematics, vol. 1, Atlantis Press/World Scientific (Paris–Amsterdam, 2008).

  3. Bagley R.W., Peyrovian M.R.: A note on compact subgroups of topological groups. Bull. Austral. Math. Soc. 33, 273–278 (1986)

    Article  MathSciNet  MATH  Google Scholar 

  4. A. Bouziad, Every Čech-analytic Baire semitopological group is a topological group, Proc. Amer. Math. Soc., 24 (1998), 953–959.

  5. Castellini G.: Compact objects, surjectivity of epimorphisms and compactifications. Cahiers Topologie Géom. Difféerentielle Catég. 31, 53–65 (1990)

    MathSciNet  MATH  Google Scholar 

  6. Castellini G.: Regular closure operators and compactness. Cahiers Topologie Géom. Différentielle Catég. 33, 21–31 (1992)

    MathSciNet  MATH  Google Scholar 

  7. G. Castellini, Categorical Closure Operators, Birkhäuser (Boston, MA, 2003).

  8. Clementino M., Tholen W.: Tychonoff’s theorem in a category. Proc. Amer. Math. Soc. 124, 3311–3314 (1996)

    Article  MathSciNet  MATH  Google Scholar 

  9. Clementino M.M., Giuli E., Tholen W.: Topology in a category: compactess. Portugal. Math. 53, 397–433 (1996)

    MathSciNet  MATH  Google Scholar 

  10. D. Dikranjan and E. Giuli, Compactness, minimality and closedness with respect to a closure operator, in: Categorical Topology and its Relation to Analysis, Algebra and Combinatorics (Conference Proceeding, Prague, 1988), World Scientific (Singapore, 1989), pp. 284–296.

  11. Dikranjan D., Giuli E.: Factorizations, injectivity and compactness in categories of modules. Comm. Algebra 19, 45–83 (1991)

    Article  MathSciNet  MATH  Google Scholar 

  12. D. Dikranjan and W. Tholen, Categorical Structure of Closure Operators, Kluwer Academic Publishers (Dordrecht, 1995).

  13. Dikranjan D., Tonolo A.: On characterization of linear compactness. Riv. Mat. Pura Appl. 17, 95–106 (1995)

    MathSciNet  MATH  Google Scholar 

  14. D. Dikranjan, I. V. Prodanov and L. N. Stoyanov, Topological Groups: Characters, Dualities and Minimal Group Topologies, Pure and Applied Mathematics, Marcel Dekker (1989).

  15. Dikranjan D., Uspenskij V.V.: Categorically compact topological groups. J. Pure Appl. Algebra 126, 149–168 (1998)

    Article  MathSciNet  MATH  Google Scholar 

  16. Ellis R.: A note on the continuity of the inverse. Proc. Amer. Math. Soc. 8, 372–373 (1957)

    Article  MathSciNet  MATH  Google Scholar 

  17. Ellis R.: Locally compact transformation groups. Duke Math. J. 24, 11–125 (1957)

    Article  MathSciNet  MATH  Google Scholar 

  18. Fay T.: Compact modules. Comm. Algebra, 16, 1209–1219 (1988)

    Article  MathSciNet  MATH  Google Scholar 

  19. Fay T.: Remarks on the Mal’cev completion of torsion-free locally nilpotent groups. Cahiers Topologie Géom. Différentielle Catég. 35, 5–84 (1994)

    MATH  Google Scholar 

  20. Fay T., Joubert S.: Relative injectivity. Chinese J. Math. 22, 65–94 (1994)

    MATH  Google Scholar 

  21. Fay T., Joubert S.: Categorical compactness for rings. J. Austral. Math. Soc. Ser. A 59, 313–329 (1995)

    Article  MathSciNet  MATH  Google Scholar 

  22. Fay T., Joubert S., Schoeman M. J.: A test criterion for categorically compact rings. Suid–Afrikaanse Tydskr. Natuurwetenskap Tegnol. 12, 89–90 (1993)

    MathSciNet  MATH  Google Scholar 

  23. Fay T., Walls G.: Compact nilpotent groups. Comm. Algebra 17, 2255–2268 (1989)

    Article  MathSciNet  MATH  Google Scholar 

  24. T. Fay and G. Walls, Categorically compact locally nilpotent groups, Comm. Algebra, 18 (1990), 3423–3435; A corrigendum: Comm. Algebra, 20 (1992), 1019–1022.

  25. Fay T., Walls G.: Completions and categorical compactness for nilpotent groups. Quaestiones Math. 17, 437–451 (1994)

    Article  MathSciNet  MATH  Google Scholar 

  26. Fay T., Walls G.: A characterization of categorically compact locally nilpotent groups. Comm. Algebra 22, 3213–3225 (1994)

    Article  MathSciNet  MATH  Google Scholar 

  27. Fay T., Walls G.: Regular and normal closure operators and categorical compactness for groups. Appl. Categ. Structures 3, 261–278 (1995)

    Article  MathSciNet  MATH  Google Scholar 

  28. T. Fay and G. Walls, \({\bar{R}}\)-groups, J. Algebra, 212 (1999), 375–393.

  29. Fernández M., Tkachenko M.: Subgroups of paratopological groups and feebly compact groups. Appl. Gen. Topol. 15, 235–248 (2014)

    Article  MathSciNet  MATH  Google Scholar 

  30. H. Herrlich, G. Salicrup and G. E. Strecker, Factorizations, denseness, separation, and relatively compact objects, Topol. Appl., 27 (1987), 157–169.

  31. Joubert S.: Categorically compact rings and modules. Chinese J. Math. 20, 347–365 (1992)

    MathSciNet  MATH  Google Scholar 

  32. Manes E. G.: Compact Hausdorff objects. General Topol. Appl. 4, 341–360 (1974)

    Article  MathSciNet  MATH  Google Scholar 

  33. A. A. Klyachko, A. Yu. Olshanskii and D. V. Osin, On topologizable and non-topologizable groups, Topol. Appl., 160 (2013), 2104–2120.

  34. Liukkonen J.: Dual spaces of locally compact groups with precompact conjugancy classes Trans. Amer. Math. Soc. 180, 85–108 (1973)

    Article  MathSciNet  MATH  Google Scholar 

  35. G. Lukács, Compact-like Topological Groups, Res. Exp. Math., vol. 31, Heldermann Verlag (Lemgo, 2009).

  36. Lukács G.: Hereditarily non-topologizable groups. Topology Proceedings 33, 269–275 (2009)

    MathSciNet  MATH  Google Scholar 

  37. D. Montgomery and L. Zippin, Topological Transformation Groups, Interscience Publ. (New York, 1955).

  38. Reznichenko E.: Extension of functions defined on products of pseudocompact spaces and continuity of the inverse in pseudocompact groups. Topol. Appl. 59, 233–244 (1994)

    Article  MathSciNet  MATH  Google Scholar 

  39. D. J. S. Robinson, A Course in the Theory of Groups, Springer-Verlag (New York, 1996).

  40. Sánchez I.: Dense subgroups of paratopological groups. Topol. Appl. 196, 241–248 (2015)

    Article  MathSciNet  MATH  Google Scholar 

  41. Sanchis M., Tkachenko M.: Totally Lindelöf and totally \({\omega}\)-narrow paratopological groups. Topol. Appl. 155, 322–334 (2008)

    MathSciNet  MATH  Google Scholar 

  42. M. Stroppel, Locally Compact Groups, Textbooks in Mathematics, European Mathematical Society (Stuttgart, 2006).

  43. Ušakov V. I.: A certain class of topological groups. Soviet Math. Dokl. 3, 682–685 (1962)

    Google Scholar 

  44. Wu T. S., Yang J. S.: \({\overline{FC}}\)-groups and their generalizations. J. London Math. Soc. 43(2), 96–106 (1991)

    Article  MathSciNet  MATH  Google Scholar 

  45. Wu T. S., Yu J. K.: Compactness properties of topological groups. Michigan Math. J. 19, 299–313 (1972)

    Article  MathSciNet  MATH  Google Scholar 

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Correspondence to I. Sánchez.

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The first author was supported by CONACYT (Mexico), grant number 57142.

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Juárez-Anguiano, H., Sánchez, I. c-compactness in locally compact groups and paratopological groups. Acta Math. Hungar. 152, 314–325 (2017). https://doi.org/10.1007/s10474-017-0725-3

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  • DOI: https://doi.org/10.1007/s10474-017-0725-3

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